EP0811712B1 - Thread clamp for a feeding gripper and feeding gripper with such a clamp - Google Patents

Description

The invention relates to a thread clamp for a rapier gripper according to the preamble of claim 1 and a rapier weaving machine with rapier gripper.

Such thread clamps are known from EP-A-624 671. The thread clamp contains a first holding member and a needle-shaped second holding member. The first and second holding members are assigned to one another in such a way that a clamping gap with a curved cross-sectional shape is formed between them. The clamping gap has a continuously increasing cross-sectional contour and constant width or decreasing width in the direction in which the thread is taken up.

The thread clamp has the disadvantage that on hair-fine weft threads with a smooth surface, the clamping area leaves pressure marks on the weft thread.

The invention as characterized in the claims solves the problem of improving the known thread clamp in order to remedy the deficiency mentioned.

The longitudinal arrangement of the deflecting member in the clamping area creates additional deflecting points, which increases the looping length and a additional frictional contact is achieved, so that the weft thread can be held with a lower overall clamping force.

Advantageous embodiments of the thread clamp result from the dependent claims. A gripper with thread clamp is characterized by the features of claim 8.

The invention is explained below with reference to the accompanying drawings.

Fig. 1

Eine räumliche Ansicht eines bekannten Bringergreifers mit Fadenklemme;

Fig. 2

eine erste Ausführungsform einer erfindungsgemässen Fadenklemme in auseinandergezogener Darstellung;

Fig. 3

einen Querschnitt der Fadenklemme im Bereich der trogförmigen Ausnehmung;

Fig. 4

eine räumliche Darstellung eines Teils eines Bringergreifers mit einer Fadenklemme gemäss Fig. 2;

Fig. 5

einen Schnitt in einer vertikalen Ebene entlang der Linie V-V in Fig. 4, aus welchen der Verlauf des Schussfadens im Klemmbereich ersichtlich ist;

Fig. 6

eine zweite Ausführungsform einer erfindungsgemässen Fadenklemme in auseinandergezogener Darstellung;

Fig. 7

eine räumliche Darstellung eines Teils eines Bringergreifers mit einer Fadenklemme gemäss Fig. 6;

Fig. 8

einen Schnitt in einer vertikalen Ebene entlang der Linie VIII-VIII in Fig. 7, aus welcher der Verlauf des Schussfadens im Klemmbereich ersichtlich ist.

Show it:

Fig. 1

A three-dimensional view of a known gripper with thread clamp;

Fig. 2

a first embodiment of an inventive thread clamp in an exploded view;

Fig. 3

a cross section of the thread clamp in the region of the trough-shaped recess;

Fig. 4

a spatial representation of part of a bringer gripper with a thread clamp according to FIG. 2;

Fig. 5

a section in a vertical plane along the line VV in Figure 4, from which the course of the weft thread in the clamping area can be seen.

Fig. 6

a second embodiment of a thread clamp according to the invention in an exploded view;

Fig. 7

a spatial representation of part of a bringer gripper with a thread clamp according to FIG. 6;

Fig. 8

a section in a vertical plane along the line VIII-VIII in Fig. 7, from which the course of the weft thread in the clamping area can be seen.

1 shows a rapier gripper with a rapier head 1 and a known thread clamp 2, in which a weft thread 3 is held. The thread clamp 2 is mounted on the hook head 1. The gripper head 1 is attached to a gripper belt 4.

This illustration shows the rapier gripper in a position during the insertion process in which the weft thread 3 has been gripped. It is pointed out that the bringer grippers according to FIGS. 4 and 7 are shown in the same position.

2 is referred to. The thread clamp essentially consists of a first holding member 11, a second holding member 12, a retaining member 13, a sleeve 14, a strip-shaped spring-elastic deflection element 15, a guide body 16 and a two-armed lever 17.

The first holding member 11 is an elongated body with a portion 18 formed at one end, a guide portion 19 spaced from the portion 18 is formed on the body 11 and a holding section 20 which is tapered toward the other end of the body 11. A shoulder 21 is formed on the holding section 20, which forms a stop for the weft thread and prevents the weft thread from being pulled through in the longitudinal direction of the thread clamp. A section 22 is formed in section 18, into which the second holding member 12 can be inserted at one end. The guide section 19 has a recess 23 into which the second holding member 12 can be inserted. In the holding section 20, a trough-shaped recess 24, which runs towards the end of the body 11, is formed, above which the second holding member 2 comes to rest.

The second holding member 12 is needle-shaped with a circular cross section and has a pin 25. The sleeve 14 has a through hole 26. The retaining element is a leaf spring 13 which has a through hole 27 with a countersink and an elongated hole 28.

The deflecting member 15 has two through bores 30, 31 which are formed in an end section or in a shoulder 32. The other end section 33 is wedge-shaped, the tip forming the free end and a guide surface 34 being formed. The surface 35 between the wedge-shaped end section 33 and the shoulder 32 is designed as a deflection surface with a slight slope. The edges of the guide surface and the deflecting surface are advantageously rounded. The guide body 16 is a hollow body which has a guide section 36 for the weft thread at one end. Furthermore, two through holes 37 are provided in the guide body 16.

In the assembled state, the second holding member 12 is mounted at one end in the bore 22 serving as a bearing point in section 18, laterally guided and supported in the recess 23 serving as a bearing point and arranged at a distance from the inner surface of the trough-shaped recess 24.

As shown in FIG. 3, a gap 41 is formed, which is delimited on the one hand by the inner surface 42 of the trough-shaped recess 24 and on the other hand by the outer surface 43 of the needle 2. As a result of the arrangement of the needle 2 in the body 11 described above, the gap 41 has a curved cross-sectional shape with a constant width in the direction in which the thread is taken up and a continuously increasing cross-sectional contour. The gap width is at least 0.005 mm.

This configuration of the trough-shaped recess 24 increases the wrap through the weft thread to be drawn in (not shown) and consequently the surface friction.

The second holding member 12 is mounted on the first holding member by means of the leaf spring 13, the sleeve 24 and a screw. In order to ensure a perfect entry of a weft thread, the second holding member 12 has a bent section 38 at the free end, so that an essentially V-shaped inlet gap 39 is formed when the holding member is mounted.

The deflecting member 15 is arranged adjacent to the longitudinal side of the first holding member 11 such that a free space is formed between the tip of the deflecting member 15 and the free end of the holding section 20 of the first holding member 12. The guide body 16 is in contact Arranged on the deflection member 15 so that the guide section 36 comes to rest in the area of the V-shaped inlet gap 39 or projects beyond it. The deflection member 15 and the guide body 16 are fastened to the first holding member 11 by means of screws 40 (FIG. 4).

The course of the weft thread 3 in the thread clamp described above and the effect thereof is explained with reference to FIGS. 4 and 5.

When the weft thread 3 is picked up by the rapier gripper, the weft thread held at one end 51 is introduced into the inlet gap 39 of the thread clamp by the guide section 52 on the rapier head 1 by the linear movement of the rapier gripper. Because the weft thread is held, the weft thread is further drawn into the thread clamp and then runs approximately as shown in FIG. 5. If the holding force caused in the thread clamp reaches a certain value, the holding of the weft end 51 is released and the weft thread 3 is inserted into the shed (not shown) by the rapier gripper (FIG. 4).

As can be seen from FIG. 5, a section 53 of the weft thread lies in the gap 41 (FIG. 3) and wraps around the second holding member 12. As already mentioned, the gap 41 has a constant width and increasing cross-sectional contour in the receiving direction. With this formation of the gap 41, the surface friction and consequently the holding force will increase with increasing depth of penetration of the weft thread. In addition to the deflection of the weft thread 3 in the gap 41, a first deflection point 54 of the weft thread is deflected by the deflection element 15 and finally a second deflection point 55 by the Guide body 16 created. Because the deflection points 54, 55 are at different levels, the weft thread 3 is essentially S-shaped and the loop length is greater. It is essential to the invention that the vertical thread section lies in the S-shaped thread path between the side surfaces of the resilient deflection member 15 and the guide body 16.

The thread clamp shown in Fig. 6 has the same structure. In the case of this thread clamp, an essentially strip-shaped insert 61 is provided in order to form a clamping point for the weft thread 3 which, by selecting different heights, results in a different clamping effect for this easily replaceable part. The insert 61 is provided with a through hole 62 at one end and has an extension 63 in which a through hole 64 is formed. The other end portion 65 of the insert tapers off. The surface opposite the extension 63 and starting from the tip is designed as a curved deflection surface 66 with a rounded surface.

As can be seen from FIG. 7, the tips of the deflection member 15 and the insert 61 are at different levels, as a result of which an inlet gap for a weft thread is present on the thread clamp in the assembled state (FIG. 7).

As FIG. 8 shows, the course of the weft thread 3 is essentially the same as in FIG. 5. As mentioned above, an additional clamping point is provided, which is formed from the deflection element 15 and the insert 61. During the insertion of the weft thread 3 into the thread clamp, the weft thread is between the deflection element 15 and the Insert 61 guided, wherein the inlet gap formed by sections 34 and 65 enables this insertion. Dumlenkorgan 15 is elastically deformed by the weft thread 3 and therefore exerts a holding force on the weft thread 3 corresponding to the thread thickness.

From the above description of the thread course it can be seen that the action of the weft thread 3 is distributed in a particularly advantageous manner over the held thread section due to the additional holding force, so that pressure points in the yarn and correspondingly less fabric are avoided.

The thread clamp contains a first holding member 11 and a second holding member 12, which form a clamping area and a retaining member 13 for the second holding member, a deflection member 15 and a guide body 16. The deflection member 15 is arranged between the guide body and the first holding member and together with the guide body on screwed first retaining member. The deflection element creates additional deflection points and an additional clamping zone, so that additional frictional contact is achieved and consequently the weft thread can be held with an overall lower clamping force.

Claims (8)

1. Thread clamp for a bringer rapier of a rapier weaving machine, which thread clamp has a first holding member (11) with a recess (24) and a second needle-shaped holding member (12) between which a clamping gap (41 with a curved cross-sectional shape is present in order to hold the thread, wherein the clamping gap has a continuously increasing cross-sectional contour and a constant or decreasing width in the take-up direction of the thread,
      characterised in that a deflection member (15) is arranged alongside the first holding member (11) in order to form a first deflection location (54) for the thread (3) in the region of the recess (24); and in that a guide body (16) is arranged parallel to the deflection member (15) in order to form a second deflection location (55) for the thread (3), with the first and the second deflection locations (54, 55) lying at different levels in order to achieve a substantially S-shaped thread deflection and to form a clamping section for the thread (3) between the first and the second deflection locations (54, 55).
2. Thread clamp in accordance with claim 1 characterised in that an insert (61) can be inserted between the deflection member (15) and the guide body (16) in order to change the clamping zone for the thread (3).
3. Thread clamp in accordance with claim 1 or claim 2 characterised in that the deflection member (15) is made of elastic material, in particular of spring steel sheet, and is substantially strip-shaped.
4. Thread clamp in accordance with one of the claims 1 to 3 characterised in that the guide body (16) consists of sheet metal.
5. Thread clamp in accordance with one of the claims 1 to 4 characterised in that the elastic deflection member (15) and the guide body (16) are secured to the first holding member (11).
6. Thread clamp in accordance with one of the claims 2 to 4 characterised in that the deflection member (15), the insert (61) and the guide body (16) are secured to the first holding member (11); and in that the first holding member (11) has a holding section (20) which is executed to taper in the direction towards the thread entry side in order to provide a free space between the holding section and the deflection member.
7. Bringer rapier with a gripper head (1) and with a thread clamp (2) in accordance with one of the claims 1 to 6 characterised in that the thread clamp (2) is secured to the gripper head by means of screws in such a manner that the thread clamp is arranged on the side of the gripper head facing the shed apex.
8. Rapier weaving machine with a bringer rapier in accordance with claim 8.