EP1699724B1 - Yarn tension device - Google Patents

Abstract

The invention relates to a yarn tension device (F) having a fixed tensioning surface (1) and a moving tensioning surface (2) and having yarn guiding elements (L1, L2, 8), which define the yarn path (x) through the yarn tension device (F) while situated upstream and downstream from the fixed tensioning surface (1). According to the invention, at least the upstream yarn guiding element (L1, 8) is, in the tensioning position, shifted downward so that it is off-center relative to the upper side of the fixed tensioning surface (1), and the yarn tension device comprises an adjusting device (SF) with which the relative position between the fixed tensioning surface (1) and at least the upstream yarn guiding element (L1, 8) can be altered in directions essentially perpendicular to the fixed tensioning surface (1).

Description

The invention relates to a yarn brake specified in the preamble of claim 1 Art.

In the out EP-A-04 53 012 known yarn brake of this type, the movable braking surface is a leaf spring which is pivotally mounted in the housing of the yarn brake with elastic bias toward the fixed braking surface and contacted in the braking position, the fixed and cylindrical braking surface. The solid cylindrical braking surface is acted upon by spring force via a lever about a parallel to the cylinder axis pivot axis in the housing to a predetermined braking position, in contact with the leaf spring is formed. In this braking position, the upstream thread eyelet is off-center offset towards the top of the fixed braking surface, so that the thread is deflected in the thread eyelet and around the fixed braking surface. In the release position, the fixed braking surface by means of simultaneously activating a pneumatic threading lever about the pivot axis on the housing completely pivoted out of the thread running path between the eyelets, while the movable braking surface is intercepted at a stop so that it does not interfere with the thread running path, but that a wide free passage between the eyelets is formed in order to automatically thread a new thread with compressed air in the release position can.

In the out WO03 / 033385 known, including magnetically actuated yarn brake the fixed braking surface is arranged on a magnetic body in the housing of the yarn brake. The Fadenleitelemente upstream and downstream of the fixed braking surface are eyelets with circular openings and define the yarn path through the yarn brake. The movable braking surface is a spring blade, which is held on a flap which is pivotable about a to the thread running path approximately parallel adjusting axis. In the braking position of the thread brake, the flap is closed. The braking effect is controlled by magnet loading of the spring blade against the fixed braking surface. In the unfolded position of the flap (release position), the movable braking surface is lifted from the fixed braking surface. In some applications no braking effect for the thread running through the thread brake thread is useful, eg. B. with weak or sticky thread qualities. In such a Case, the flap remains open. Since the thread running path is determined by the thread brake by the specially selected relative position of the yarn guide with respect to a normal braking operation so that the braked thread does not stimulate the movable braking surface with weak braking action to vibration, can in the release position despite open flap of not braked thread on rub the fixed braking surface. A single predetermined relative position of the yarn guide elements thus represents a non-optimal compromise both for yarn materials that are not braked, as well as for thread materials that may be weakly braked, is. It should be noted that in many cases the thread in the upstream thread eye enters with a circulating movement, which is generated by a preceding yarn feeding device, and which can stimulate the thread in the yarn brake to vibrations.

At the US-A-4,817,681 known yarn brake is a release position adjustable, in which between the solid brake element defining surface and the movable brake element defining leaf spring, a gap is set through which the defined by the upstream and downstream thread eyelets thread running path. The eyelets are positioned in relation to the gap in the release position of the thread brake so that then no longer actively braked, but still maintains contact between the thread and the solid braking surface defining surface.

At the US-A-3,929,169 known yarn brake the fixed braking surface is adjusted by means of a cam drive in a release position in which the fixed braking surface still protrudes beyond a straight line, which would correspond to a straight yarn path and connects the lowest points of the opening circles of both yarn loops. This means that the thread is not actively braked, but still rubs against the fixed braking surface.

The invention has for its object to improve a thread brake of the type mentioned in that for different thread materials that are either slowed down or go through unrestrained, each optimal thread running conditions can be achieved.

The stated object is achieved with the features of claim 1.

For thread materials that require braking, possibly only a slight braking, it is advantageous if at least the upstream thread eye is off-center offset towards the top of the fixed braking surface, so that the incoming thread is clean and calm guided along the fixed braking surface even if it enters the upstream eyelet with one revolution. This results in braking optimal thread running conditions. The offset down, however, would be impractical for thread materials that are not to be braked, because then the thread would be undesirably guided and rubbed on the fixed braking surface under the passage tensile force. Thanks to the adjusting device, the relative position between the fixed braking surface and at least the upstream thread eyelet can be changed so that optimal thread running conditions are present even for thread material not to be braked in the release position of the thread brake because the thread in the thread brake contacts neither the fixed nor the movable braking surface. The thread brake then has no effect on the yarn path and only needs to be changed over and opened, but not dismantled. Since in many cases of use of such yarn brakes at least the upstream yarn eyelet must have a predetermined and unchangeable relative position with respect to a device from which the thread enters the yarn brake, the fixed braking surface is expedient in directions substantially perpendicular to its upper side relative to at least upstream thread eye adjustable. By adjusting the fixed braking surface relative to the eyelet can be made for the respective processed thread material optimum relative position between the eyelet and the fixed braking surface, either with regard to an optimal braking effect without thread tension fluctuations even with low braking effect, or for thread materials that ever should not be braked, and for which the yarn brake is open. In the first case, the yarn eyelet is slightly offset from the upper surface of the fixed braking surface, ie away from the movable braking surface, so that the yarn is guided cleanly along the fixed braking surface even with a tendency to vibrate from an orbital motion caused by the upstream becomes. In the second case, the upper side of the fixed braking surface is offset downwards relative to at least the upstream yarn eyelet, so that the yarn, even if it approaches the eyelet with a circulating movement, passes by the fixed braking surface and is not braked. In applications in which the assignment of at least the upstream thread eyelet may be changed to a device issuing the thread, it may be appropriate to adjust at least the upstream eyelet in directions substantially perpendicular to the fixed braking surface. The fixed braking surface then does not need to be adjustable. Structurally simple, the fixed braking surface is adjusted in a sliding guide of the housing of the yarn brake. The sliding guide can run substantially perpendicular to the top of the fixed braking surface. At least two predetermined detent positions are provided for the fixed braking surface defining two optimum relative positions. Optionally, even more than two locking positions are provided. The fixed braking surface is manually adjustable between the locking positions, z. B. by pressure with the hand in one or the other direction of adjustment until the fixed braking surface has taken the respective detent position. Optionally, an auxiliary drive for adjusting the fixed braking surface, with or without magnetic body, provided, which simplifies handling. The auxiliary drive can optionally operate remotely, z. B. by means of a pneumatic cylinder or an electric motor. If the position of the upstream thread eyelet is not necessarily unchangeable relative to a device arranged in front of it, the eyelet is adjusted relative to the upper side of the fixed brake surface. This can take place in that the housing cheek containing the thread eye of the thread brake is adjusted, or only the thread eyelet in the housing cheek. The eyelet with a circular opening can either be moved back and forth in a sliding guide of Gehäusewange with defined locking positions, or raised or lowered by means of an eccentric by rotating relative to the upper side of the fixed braking surface. Appropriately, both eyelets can be adjusted together or individually.

In the case of a suture eyelet having a circular aperture, it is desirable to select the offset from the fixed braking surface downwardly in the braking position such that the distance, seen perpendicular to the surface, between the fixed braking surface and the highest point of the circle of the aperture is between about 5 to 35%, preferably about 20% of the circle diameter. For thread materials that are not to be braked, however, the relative position is adjusted until the distance between the fixed braking surface and the highest point of the circle at least half to the whole Circular diameter is, preferably even more than the whole circle diameter.

When the fixed braking surface is attached to a magnetic body, the magnetic body is displaced together with the fixed braking surface.

The locking positions are positively and resiliently acted upon. This allows a comfortable handling. For safety reasons, a releasable locking device can be provided for each locking position, which must be solved only if an adjustment is made.

Fig. 1

eine schematische Seitenansicht einer Fadenbremse, in einer Bremsstellung,

Fig. 2

eine schematische Seitenansicht der Fadenbremse, in einer nicht bremsenden Lösestellung,

Fig. 3

eine schematische, um 90° gedrehte Detailansicht in Fadenlaufrichtung, analog zu Fig. 1, und

Fig. 4

eine schematische um 90° gedrehte Detailansicht in Fadenlaufrichtung analog zu Fig. 2,

Fig. 5

eine konkrete Ausführungsform einer Fadenbremse in einem Teilschnitt senkrecht zur Fadenlaufrichtung, und in einer Lösestellung,

Fig. 6

eine Schnittansicht zu Fig. 5 in der Schnittebene VI-VI,

Fig. 7

eine Schnittansicht der Fadenbremse in der Bremsstellung, in einer Schnittebene senkrecht zur Fadenlaufrichtung,

Fig. 8

eine Schnittansicht zu Fig. 7 in der Schnittebene VIII-VIII,

Fig. 9

eine Seitenansicht der Fadenbremse, beispielsweise von Fig. 7, mit ei- nem teilweisen Schnitt in der Schnittebene IX-IX von Fig. 10, und

Fig. 10

eine Draufsicht, mit einem Teilschnitt in der Schnittebene X-X von Fig. 9.

Embodiments of the subject invention will be explained with reference to the drawing. Show it:

Fig. 1

a schematic side view of a yarn brake, in a braking position,

Fig. 2

a schematic side view of the yarn brake, in a non-braking release position,

Fig. 3

a schematic, rotated by 90 ° detail view in the thread running direction, analogous to Fig. 1 , and

Fig. 4

a schematic rotated by 90 ° detail view in the thread running direction analogous to Fig. 2 .

Fig. 5

a concrete embodiment of a yarn brake in a partial section perpendicular to the thread running direction, and in a release position,

Fig. 6

a sectional view too Fig. 5 in section VI-VI,

Fig. 7

a sectional view of the thread brake in the braking position, in a sectional plane perpendicular to the thread running direction,

Fig. 8

a sectional view too Fig. 7 in the section plane VIII-VIII,

Fig. 9

a side view of the yarn brake, for example of Fig. 7 , with a partial section in the section plane IX-IX of Fig. 10 , and

Fig. 10

a plan view, with a partial section in the section plane XX of Fig. 9 ,

One in the Fig. 1 and 2 In a side view only schematically illustrated yarn brake F has a fixed braking surface 1 on a magnetic body 3, which is adjustable in a sliding guide approximately perpendicular to the top of the fixed braking surface 1. For cooperation with the fixed braking surface 1, a movable braking surface 2 is provided, for example, with a flap, not shown, about an adjusting axis 29 of the in Fig. 1 shown braking position in the in Fig. 2 shown unfolded release position can be brought. The braking effect between the braking surfaces 1, 2 is generated and modulated magnetically in the braking position via the magnetic body 3. Optionally, the movable braking surface 2 is additionally or even only pressed by a spring, not shown, or by its own elasticity against the fixed braking surface 1. Upstream and downstream of the fixed braking surface 1 yarn guide elements L1 and L2 are provided which define a certain yarn path x through the yarn brake F.

The thread guiding elements L1, L2 are eyelets 8 with circular openings 9. The thread guiding elements L1, L2 are in housing walls 6, 7 of the yarn brake F in certain relative positions against (the plane) of the top of the fixed braking surface 1 positioned.

In the in Fig. 1 shown brake position are indicated with Y circular centers of the openings 9 of the eyelets 8 slightly offset from the fixed braking surface 1 down. According to Fig. 3 is the offset of the circular center y down adjusted so that the distance a between the top of the fixed braking surface 1 and a highest point 11 of the opening 9 is about 5 to 35% of the circular diameter d. This ensures that even when the thread enters the upstream thread eye 8 with one revolution, (in Fig. 1 indicated by dashed lines), the thread is guided clean along the top of the fixed braking surface 1 and vibrations from the orbital motion are largely attenuated. The downstream thread eyelet 8 can be positioned in the same way as the upstream eyelet 8. However, this is not absolutely necessary. The downstream thread eyelet 8 could possibly be aligned with its circular center Y on the solid braking surface 1 or above.

The sliding guide defines at least a first and a second detent position R1, R2 for the magnetic body 3 and the fixed braking surface 1. Between the detent positions R1, R2, the fixed braking surface 1 can be adjusted by manual pressure up or down, or by means of an auxiliary drive. 4 and an operation 5. In the in Fig. 1 shown, upper detent position R1 is the aforementioned, the braking position associated relative position between the Fadenleitelementen L1, L2 and the fixed braking surface 1 before.

In the in Fig. 2 shown release position of the yarn brake B, this relative position is changed. Namely, at least the circular center Y of the upstream yarn eyelet 8 (if necessary, that of the downstream thread eyelet 8) opposite to the top of the fixed braking surface 1 opposite Fig. 1 and 3 offset upwards. According to Fig. 4 is now the distance a 'between the top of the fixed braking surface 1 and the highest point 11 of the circle of the opening 9 about 80% of the circle diameter d. As in Fig. 4 , indicated diagrammatically to the right at 10, the adjustment range can be so large that the distance a 'between the highest point 11 of the circle of the opening 9 and the top of the fixed braking surface 1 is more than half the circle diameter d or even greater than that Circle diameter d.

In an alternative, not shown, the yarn brake F Fadenleitelemente L1, L2, at least the upstream yarn eyelet 8, in the respective Gehäusewange 6 and 7 relative to the upper side of the fixed braking surface 1 adjustable. For this purpose, the adjustable eyelet 8 is held, for example, in a sliding guide in the Gehäusewange 6 and 7, which defines the at least two spaced apart in the vertical direction locking positions R1, R2. Alternatively, the thread eye is either formed itself with eccentric opening or contained in an eccentric, so that can be changed by rotating in the Gehäusewange the high position of the circular center y in relation to the top of the fixed braking surface 1. Optionally, even the entire Gehäusewange 6 or 7 adjusted with the eyelet 8 when the above-mentioned relative positions must be changed (not shown).

In the Fig. 5 to 10 Various views and sectional views of a particular embodiment of a yarn brake F are shown, which is a magnetically controlled yarn brake of the type TEC.

The yarn brake has the adjusting device SF for adjusting the arranged on the magnetic body 3, fixed braking surface 1 between the at least two locking positions R1, R2, based on the Fig. 1 to 4 are explained. The not shown in the figures, the movable braking surface is supported on a flap 18 which is about the adjusting axis 29 of the housing of the yarn brake from the braking position shown in the direction of an in Fig. 5 indicated arrow can be opened to bring the yarn brake in a release position.

On a housing part 12, two approximately V-shaped depressions 20, 19 are formed, which extend approximately in the direction of yarn travel. A detent element 13, which is formed in the basic train U-shaped with two legs, is connected to a here, for example, curved cover 16, which in turn connected to the magnetic body 3 and formed in yielding or yielding. The locking part 13 may be a one-piece plastic injection molded part with the cover 16. For additional securing of the two latching positions R1, R2 compression springs 14 may be provided on retaining pins 15. Furthermore, a blocking device is provided, which comprises a lever 17 with a blocking lug 25. The lever 17 is pivotally connected to one of a connected to the magnetic body 3 flange plate 21 axle journal 22 between the legs of the locking member 13 and has a spring arm 26, the lever 17 in the in Fig. 10 indicated blocking position acted upon. In the blocking position, the blocking lug 25 engages, for example, over a leg of the latching part 13, so that it can not escape from the latching recess 19 or 20 against the spring 14 as long as the lever 17 is in Fig. 10 is not rotated so far clockwise that the blocking lug 25 is displaced into the space between the legs of the locking part 13.

Is the lever 17 from the in Fig. 10 shown blocking position counterclockwise rotated so far that the blocking lug 25 of the in Fig. 10 right leg of the blocking part 13 is released, then can be by pressure, for example, on the magnet housing 3 and in the direction Fig. 10 , either manually or with an auxiliary drive up or down, the respective latching position R1, R2 set. If then, if necessary, the lever 17 is released remotely, then presses the spring arm 26, the blocking lug 25 back into the in Fig. 10 shown blocking position. Optionally, this movement is supported by pivoting the lever 17 in the counterclockwise direction.

The lever 17 is rotatably mounted with a sleeve member 23 on the pivot pin 22 and is secured by a spacer sleeve 24 against rising.

In the FIGS. 5 and 6 the fixed braking surface 1 is fixed in the locking position R2. The distance a 'between the yarn path X and the highest point 11 of the circular Opening 9 of the yarn guide element L1 or L1 and L2 defining yarn eyelet is for example 5.5 mm. The flap 18 can remain in the unfolded position in this case, since the thread along the yarn path X neither the movable braking surface nor the fixed braking surface 1 can contact. But it is also possible, for safety's sake, the flap 18 in Fig. 5 to unfold in a clockwise direction. The one in the blocking position of Fig. 10 standing lever 17 prevents an automatic movement of the magnetic body 3 from the selected locking position R2.

In the in FIGS. 7 and 8 shown braking position of the yarn brake F is the magnetic body 3 fixed to the fixed braking surface 1 in the other locking position R1 and secured by the lever 17 with the blocking lug 25. The distance a between the fixed braking surface 1 and the highest point of the circular opening 9 at least the upstream thread eyelet or the thread guide L1 is only 0.5 mm, ie the distance a between the yarn path x and the fixed braking surface corresponds to the dimension of 0 , 5 mm.

Should be in the braking position of FIGS. 7 and 8 the thread entering the upstream eyelet L1 with a circular motion, which is generated for example by an upstream upstream yarn feeding device, and could stimulate the thread to a vibration also perpendicular to the fixed braking surface 1, then this vibration is due to the contact of the thread with the fixed Brake surface and effectively damped in the thread eye, so that the thread runs smoothly through the thread brake. In the release position according to the FIGS. 5 and 6 the thread, which should not be braked in the thread brake anyway, if necessary, perform vibrations perpendicular to the fixed braking surface 1, without contacting the movable or the fixed braking surface 1 and to be braked.

At a suitable point of the thread brake markings can be provided which visually clearly indicate whether the locking position R1 or R2 is selected. Optionally, more than two locking positions R1, R2 are provided, or an adjustment is provided which allows a defined adjustment of the relative position of the yarn guide elements with respect to the fixed braking surface without defined locking positions.

Claims (4)

1. Yarn tensioner (F), in particular for weaving machines, comprising a fixed braking surface (1) and a movable braking surface (2), which movable braking surface (2) is adjustable between a braking position, during which the movable braking surface (2) abuts with pressure in a braking zone on the fixed braking surface (1), and a release position in which the movable braking surface (2) is lifted from the fixed braking surface (1), and yarn eyelets (L1, L2, 8) positioned upstream and downstream of the braking zone and determining the yarn running path (X) of the yarn (Y) through the yarn tensioner (F), at least the yarn eyelet being positioned upstream (L1, 8) in the braking position being offset off-centre downwardly with its circular opening (9) in relation to the fixed braking surface (1), the yarn tensioner (F) comprising an adjustment assembly (SF) for varying the relative position between the fixed braking surface (1) and at least the yarn eyelet (L1, 8) positioned upstream, in a direction substantially perpendicular to the fixed braking surface (1), characterised in that either the fixed braking surface (1) is arranged adjustably in a direction substantially perpendicular to its upper side and in relation to at least the yarn eyelet (L1, 8) positioned upstream in a sliding guidance extending substantially perpendicular to the upper side of the fixed braking surface (1), that at least two predetermined ratcheting positions (R1, R2) are provided for the fixed braking surface, the fixed braking surface (1) being adjustable manually or by means of an auxiliary drive (4) between the ratcheting positions (R1, R2), or that at least the yarn eyelet (L1, 8) positioned upstream is arranged in a housing cheek (6, 7) of the yarn tensioner (F), the housing cheek (6, 7) and the yarn eyelet (L1, 8) or the yarn eyelet (L1) in the housing cheek (6, 7) being adjustable in directions substantially perpendicular to the upper side of the fixed braking surface (1) in relation to the upper side, such that in the release position a yarn running condition for a yarn (Y) which must not be braked is established, in which the yarn (Y) neither contacts the fixed braking surface (1) nor the movable braking surface (2) along the yarn running path (X) through the yarn tensioner (F), and in which the yarn tensioner (F) does not have an influence on the yarn run.
2. Yarn tensioner according to claim 1, characterised in that in the braking position the centre (y) of the circle of the opening (9) of the yarn eyelet (8) positioned upstream is offset off-centre relative to the upper side of the fixed braking surface so far downwardly that - seen perpendicularly to the surface - the distance (a) between the upper side and the highest point (11) of the circle of the opening amounts to between about 5% to 35%, preferably about 20%, of the diameter (d) of the circle, and that the relative position is adjustable until the distance (a') amounts at least to a measure corresponding to half of or the full diameter (d) of the circle, preferably amounts to a measure even more than the full diameter (d) of the circle.
3. Yarn tensioner according to claim 1, characterised in that the fixed braking surface (1), preferably together with a solenoid body (3) on which the fixed braking surface (1) is arranged, is manually adjustable between the ratcheting positions (R1, R2).
4. Yarn tensioner according to claim 1, characterised in that the ratcheting positions (R1, R2) are defined by a form fit and by spring force, and that additionally a releasable blocking device (17, 25) is provided for the respective ratcheting position (R1, R2).

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