EP1727931B1 - Embossed tufting needle - Google Patents

Abstract

A novel tufting needle ( 4 ) is distinguished by a hollow flute ( 15 ) which is preferably symmetrical to a central plane ( 29 ) and which is bilaterally provided with chamfers ( 33, 34 ). The chamfers ( 33, 34 ) are, in an inward-located, that is, in a region lying close to the central plane ( 29 ), inclined at a small acute angle (alpha) to a reference plane ( 28 ), while in a region bordering an externally located rim (edges ( 46, 47 )), the chamfers ( 33, 34 ) are inclined at a larger acute angle (beta) to the reference plane ( 28 ). This feature improves the rigidity, the tufting properties and the mechanical strength, as well as the wear resistance of the novel tufting needle ( 4 ).

Description

The invention relates to an improved tufting needle.

Tufting needles are for example from the EP 0 874 932 B1 known. The illustrated in this document tufting needle has a base body, the holding end is held in a holding body. The other end is in a tip adjacent to an eye. Along the shaft, a thread trough extends to the eye.
From the U.S. Patent 5,189,966 is a tufting needle is known, which has on its flanks curved chamfers for a loop taker. However, she has no real groove. The shaft has a cross section in the region of the chamfers in the manner of an arch triangle.

Furthermore, from the WO 90/06391 a tufting needle is known, which is provided in the vicinity of the eye with a groove. The fillet serves to provide improved access to the thread to a loop taker or other tool. In the area of the groove, the tufting needle is flattened and mechanically weakened.

Loop grabs can hit the tufting needle in the area of the groove and reach into the groove across the needle. This results in the wear of the tufting needle as a result of material removal over time. If this is too advanced or even a breakthrough is created towards the thread channel, the tufting needle must be replaced. This has a life-limiting effect.

During this process, due to process uncertainties, the loop grabs hit the flanks of the tufting needles and miss the fillet.

It is an object of the invention to increase the service life of a tufting needle and at the same time to increase the entry space into the groove.

This object is achieved with the tufting needle according to claim 1:

The tufting needle according to the invention has a groove provided with at least one chamfer, the chamfer standing steeper at its edge lying towards the needle flank than further inside. In the words of the claim, this means that the chamfer in the vicinity of the center of the needle with the reference plane includes an acute angle α, which is smaller than a further outward acute angle β. As a result, the sliding angle between a possible gripper and the chamfer of the groove is defused. The gripper hits the chamfer in an outer area which is at the angle β. β is for example in the range of 35 ° to 50 ° and is preferably 45 °. It is thereby ensured a high level of security when receiving the thread loop, because the entry space of the gripper in the groove area is increased. The impact of the gripper on the flanks of the needle is almost avoided. Inwardly to the angle of the chamfer falls to a smaller value between 20 ° and 40 °, preferably 30 °, down. Thereby, the friction between the gripper and the groove is reduced, resulting in a reduced gripper wear and reduced wear of the tufting needle.

Due to the convex curvature or formation of the chamfer of the groove, which can be seen from the radial direction, the thickness of the wall between the chamfer and the thread groove is increased in comparison to plane chamfers. As a result, the service life of the tufting needle is increased up to a possible breakthrough of the gripper in the groove. Both factors namely the reduced friction between The needle and the gripper, as well as the thicker wall between the thread groove and the chamfer, in each case and taken together, result in a significant increase in needle life.

The needle body can be arranged in the tufting module with an angle of attack. This means that the reference plane of the tufting needle is not oriented at right angles to a contact surface of a needle bar. Such a position, which normally increases the friction between the gripper and the needle, is well tolerated by the needle according to the invention.

The needle body is preferably formed flattened. This applies in particular to the area of the groove. Also adjoining the groove portion may be formed flattened. This results in a good needle elasticity in a needle side direction and a high needle stiffness in a perpendicular side direction, which usually coincides with the material transport direction of the base material.

The tufting needle may have a thread trough. If this is not required, it can be left out if necessary.

The groove is preferably formed symmetrically with respect to a median plane. Thus it can be used in both right and left orientation.

In particular, the groove can be provided on both sides with bevels to allow the latter. The groove is preferably again oriented symmetrically to the median plane. The working method in the right orientation and in the left orientation is then the same. The cross section of the needle then has an upwardly rounded or faceted roof-like shape in the region of the groove. Despite chamfering on both sides of the groove, there are large wall thicknesses towards the thread groove.

It is both possible to facet the chamfer, whereby the individual facets can connect to each other in generous roundness. It is also possible to form the groove rounded overall. In the latter case, it thus forms an elongated saddle surface. The aforementioned flats and facets can be produced on the tufting needle by embossing. The flattened areas thus produced may laterally project beyond the unembossed other shaft. In this case, a projection of the outer edges of the thread groove in the region of the groove between about 5% and 20% of the shaft width can be achieved. This comes e.g. the stability of the tufting needle benefits.

The symmetrical arrangement of the chamfers can also lead to an improved wear behavior of the needle for another reason. It is largely prevented that the gripper scrape in unilateral thread design during the return stroke of the needle at the edge of the groove. The risk of the formation of sharp edges, which could lead to injuries of the substrate is reduced.

Further details of advantageous embodiments and developments of the invention will become apparent from the drawing, the description or claims.

Figur 1

einen Ausschnitt aus einer Barre und einem an dieser gehaltenen Tuftingnadelmodul mit mehreren parallel zueinander orientierten Tuftingnadeln in perspektivischer Darstellung,

Figur 2

das Modul nach Figur 1 in Vorderansicht,

Figur 3

das Modul nach Figur 1 in Seitenansicht,

Figur 4

einen Querschnitt durch eine Tuftingnadel im Bereich ihrer Hohlkehle,

Figur 5

eine der Tuftingnadeln der Module nach Figur 2 und 3 in Vorderansicht und

Figur 6

die Tuftingnadel nach Figur 5 in längs geschnittener Darstellung.

In the drawing, an embodiment of the tufting needle according to the invention is illustrated. Show it:

FIG. 1

a detail of a bar and a held on this tufting needle module with several parallel oriented tufting needles in perspective view,

FIG. 2

the module after FIG. 1 in front view,

FIG. 3

the module after FIG. 1 in side view,

FIG. 4

a cross section through a tufting needle in the region of its groove,

FIG. 5

one of the tufting needles of the modules FIGS. 2 and 3 in front view and

FIG. 6

the tufting needle after FIG. 5 in longitudinal section.

In FIG. 1 schematically illustrates a bar 1 with a tufting module 2 held thereon. The tufting module 2 consists of a body 3 in or on which a group of tufting needles 4 is held. The body 3 rests with a flat side on the front side 5 of the bar 1. The tufting needles 4 are aligned at a distance parallel to each other down.

The FIGS. 2 and 3 illustrate the tufting module 2 separately. How out FIG. 2 shows, the tufting needles 4 are equal to each other and flattened. With their upper end they are held in the body 3. Their ears 6 are how out FIG. 3 shows, for example, aligned with each other.

The structure of a single tufting needle 4 goes out of the FIGS. 4 . 5 and 6 out. As FIG. 6 illustrates, the tufting needle 4 on a needle body 7, which forms a up to a tip 8 extending shank 9. The tip 8 marks the center of the shaft 9. A longitudinal axis 11 which determines the longitudinal direction of the needle body 7 and the shaft 9 passes through the tip 8.

Starting from a first section 12 which can also be regarded as a clamping section and which has a substantially circular or at least rounded cross-section, a flattened section 13 extends in the direction of the tip 8. The flattened portion 13 is followed by a portion 14, which is provided with a groove 15. The section 13 is at the top by a Planar surface 16 completed. The groove 15 approaches the flat surface 16 closer to the longitudinal axis 11 at. It forms an elongated saddle-shaped indentation. In the immediate vicinity of the groove 15, the eye 6 is provided. It is surrounded by a planar annular surface 17, which is preferably arranged in a plane with the flat surface 16. Starting from the annular surface 17, a section 18 begins in which the needle body 7 tapers towards the tip 8.

As in particular from FIG. 6 it can be seen, a thread groove 19 is formed on the flat surface 16 opposite side of the tufting needle 4, which extends over the sections 13, 14 away into the eye 6 in. The cross section of the yarn channel 19 is substantially constant over its entire length. FIG. 4 illustrates the cross section of the tufting needle 4, cut along in FIG FIG. 5 registered line IV-IV. In the FIGS. 4 and 5 Different display scales are chosen. As FIG. 4 shows, the thread groove 19 is preferably formed approximately trapezoidal. On the thread groove 19 close on both sides legs 21, 22, which are bounded at the thread trough side by flat surfaces 23, 24. The flat surfaces 23, 24 close to each other at an obtuse angle. They terminate in edges 25, 26 which lie radially clearly outside an outline 27 which the shaft 9 has in the section 12. Thus, the legs 21, 22 project beyond this outline 27.

In the illustration according to FIG. 4 For example, the eyelet cut away and thus not illustrated has a vertical opening direction. This is perpendicular to a reference plane 28. This is preferably aligned parallel to the plane surface 16. The reference plane 28 extends longitudinally through the tufting needle 4 and thus includes the longitudinal axis 11. Perpendicular to the reference plane 28 is to be considered a median plane 29 which intersects the reference plane 28, wherein the intersection line is the longitudinal axis 11. The median plane 29 forms a plane of symmetry for the tufting needle 4.

Out FIG. 4 In particular, the shape of the groove 15 shows. Starting from an edge bounding the plane surface 16, a rounding 31 is provided, which merges into straight surfaces with respect to the longitudinal direction. These surfaces include a symmetrically arranged to the center plane 29 plane surface 32, which is preferably oriented parallel to the reference plane 28. On both sides of the plane surface 32 chamfers 33, 34 are arranged, which intersect the reference plane 28. The chamfers 33, 34 are arranged symmetrically to the center plane 29. In the present embodiment, the chamfers 33, 34 are faceted. Accordingly, they each contain two strip-shaped planar surfaces 35, 36 and 37, 38, which merge into a rounded or curved surface 41, 42. The surface 41 lies between the flat surfaces 35, 36. The surface 42 is located between the flat surfaces 37, 38. In addition, the chamfers 33, 34 via rounded or curved surfaces 43, 44 to the flat surface 32 at. The flat surfaces 35, 36 and 37, 38 in pairs each include an obtuse angle. This results in different angles to the reference plane 28 or a parallels to it, as in FIG. 4 is illustrated. The planar surface 38 includes a point α with a line 45 parallel to the reference surface 28. The same applies to the Flat surface 36. The flat surface 37 includes the line 45 at an acute angle β. The same applies to the plane surface 35. The angle α is smaller than the angle β. Preferably, the angle α is in the range of 20 ° to 40 °. In the present preferred embodiment, it is 30 °. The angle β is preferably in the range of 35 ° to 55 °. In the present preferred embodiment, it is 45 °. The flat surfaces 35, 37 are marginal, ie they preferably end in an edge 46, 47, which lies outside the outline 27. Thus, the outer flanks 48, 49 of the portion 14 are outside the outline 27. The flanks 48, 49 are preferably slightly curved.

The tufting needle 4 described so far operates as follows:

In use, a thread is passed through the thread groove and the eye 6. If the tufting needle 4 now stabs through a base material, the thread is pulled by the eyelet 6 through the base material. near the lower turning point of the needle 4, a loop taker (looper) is moved toward the tufting needle 4. The looper is hook-shaped. With its tip, it first strikes the plane surface 37. Due to its strong inclination to the reference plane 28 (acute angle β), a large distance between the edge 47 and the line 45 is achieved. Regardless of existing misalignment, tolerances, inaccuracies or bends the tip of the looper hits thus securely on the chamfer 34. He then slides first along the plane surface 37 along and then reaches the plane surface 38. By their lower angle of attack (smaller acute angle α) to the reference plane 28, the friction is reduced. The looper is then transferred to the planar surface 32 and beyond, so that during the needle return stroke, he can grasp the thread initially pierced by the substrate through the eye.

The curvature present in the chamfers 33, 34 leads to an enlargement of the wall thickness a, b to the yarn channel 19 at 41 and 42, respectively. Ultimately, this not only benefits the stiffness of the tufting needle 4 but also its wear resistance. Gradual removal of the existing wall leads to untoward wear only after very long use.

A novel tufting needle 4 is characterized by a preferably with respect. A center plane 29 symmetrically formed groove 15, which is provided on both sides with chamfers 33, 34. The chamfers 33, 34 have an only slightly acute angle .alpha. To a reference plane 28 in an area lying on the inside, ie lying close to the center plane 29, while they are in an outer area adjoining the edge (edges 46, 47) are inclined at a larger acute angle β against the reference plane 28. This improves the rigidity, the tufting properties and the mechanical stability and wear resistance of the new tufting needle 4.

LIST OF REFERENCE NUMBERS

1

bar

2

tufting

3

body

4

tufting

5

front

6

eyelet

7

needle body

8th

top

9

shaft

11

longitudinal axis

12, 13, 14

section

15

fillet

16

plane surface

17

ring surface

18

section

19

thread groove

21, 22

leg

23, 24

plane surfaces

25, 26

edge

27

outline

28

reference plane

29

Midplane, needle center

31

curve

32

plane surface

33, 34

chamfers

35, 36; 37, 38

plane surfaces

41, 42; 43, 44

area

45

line

46, 47

edge

48, 49

flanks

Claims (14)

1. Tufting needle (4)
   with a needle body (7), which has a blade (9) terminating in a point (8) at the end, which is provided with an eye (6) and with a furrow (15) in the vicinity thereof, wherein the direction of opening of the eye (6) is located vertically to a reference plane (28),
   wherein the furrow (15) is provided with at least one bevel (33, 34), characterised in that the bevel (33, 34) is arranged inclined to the reference plane (28) and in the vicinity of the needle centre (29) encloses with the reference plane (28) an acute angle (α), which is smaller than an angle (β), which the bevel (33, 34) encloses with the reference plane (28) at a greater lateral distance from the needle centre (29).
2. Tufting needle according to claim 1, characterised in that the needle body (7) has a flattened structure.
3. Tufting needle according to claim 1, characterised in that on the side remote from the furrow (15) the needle body (7) is provided with a thread groove (19).
4. Tufting needle according to claim 1, characterised in that the furrow (15) has the shape of an elongated saddle surface.
5. Tufting needle according to claim 1, characterised in that it is configured symmetrically with respect to a centre plane (29) located vertically to the reference plane (28) and oriented in the longitudinal direction (11) of the needle.
6. Tufting needle according to claim 1, characterised in that the furrow (15) is provided with bevels (33, 34) on both sides.
7. Tufting needle according to claim 6, characterised in that the bevels (33, 34) are configured symmetrically with respect to a centre plane (29) located vertically to the reference plane (28) and oriented in the longitudinal direction (11) of the needle.
8. Tufting needle according to claim 1, characterised in that the bevel (33, 34) extends over the entire length of the furrow (15).
9. Tufting needle according to claim 1, characterised in that the bevel (33, 34) has at least two facet faces (35, 36; 37, 38), which respectively enclose different angles (α, β) with the reference plane (28).
10. Tufting needle according to claim 9, characterised in that the facets (35, 36; 37, 38) merge into a rounded surface (41, 42).
11. Tufting needle according to claim 1, characterised in that the bevel (33, 34) is formed by an arched surface (41, 42).
12. Tufting needle according to claim 1, characterised in that in the region of the furrow (15) the blade (9) is widened relative to the rest of its width.
13. Tufting needle according to claim 1, characterised in that an end face (32), which is sunken relative to adjacent faces (16, 17), is provided in the furrow (15) between the bevels (33, 34).
14. Tufting needle according to claim 1, characterised in that the direction of opening of the eye (6) is located vertically to the reference plane (28), and that the recess is oriented parallel to the reference plane (28).

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