EP3114265B1 - Profiled pile cutter - Google Patents

Description

The invention relates to a loop gripper for tufting machines, in particular for the production of cutting edge.

Loop grippers for tufting machines are known from the prior art in various designs. For example, the US 2,090,021 a loop taker with a gripper finger, which is provided on its underside with a long two-stage cutting edge. An arranged in a loop taker cutting knife is used for targeted cutting of the recorded loops to produce Schneidflor. See also EP 1 953 289 A1 ,

Next shows the EP 0 200 810 A1 a loop gripper with a carbide insert which defines a cutting edge offset upwards from the lower edge of the loop taker. Following the cutting edge, a step is provided on which a straight edge extends to the free end of the loop taker. At the loop taker a leaf spring is arranged to be movable in the longitudinal direction of the gripper finger. By advancing or retracting the leaf spring, the gripper can be switched from a mode in which Schlingenflor is generated, in a different mode in which Schneidflor is generated.

In the production of Schneidflor running knives are usually used in addition to the grippers. A problem that occurs here is the asymmetric cut. The loops caught by the gripper tend to not exactly at their apex, but to be slightly cut laterally, resulting in a not quite uniform pile height. To remedy this problem is in the EP 1 953 290 A1 has been proposed to provide a lateral recess on the loop taker. On the other side of the loop taker a flat carbide insert is provided, which carries the cutting edge. Through the recess of the loop taker at the cutting edge is particularly narrow, so that the recorded loops are cut at least approximately at its apex.

Nevertheless, problems may arise when the slings are made of particularly slippery material. If these are displaced in the longitudinal direction of the cutting edge before or during the cutting process, the loop may warp and the cut may be unclean or off-center again.

To prevent the slipping of slings on a loop grab, the EP 767683 B1 to form a corrugated cutting edge on a loop taker for cutting pile. This serrated edge of the cutting edge prevents slippage of the recorded loops in the gripper longitudinal direction.

Next is from the US 1,907,292 a loop grab with toothed cutting edge known.

In addition, the reveals US 2,842,080 Loop gripper with stepped cutting edge for producing different pile heights.

In the production of Schneidflor with particularly slippery, but cut-resistant pile thread, this tends to dodge in front of the cutting blade. He can because of that Cut along the cutting edge are moved and ultimately cut or cut as a result of its increasing tension on the cutting edge without the cut is cleanly guided by the knife. This is especially true for easily lubricious, but poorly cut materials, such as certain plastics, such as polyester threads, or coated threads, such as those used for the production of dirt-repellent carpet use.

It is an object of the invention to provide a loop grab, which is also suitable for difficult materials.

• Der erfindungsgemäße Schlingengreifer weist einen Greiferfinger auf, der an seiner Unterseite mit einer Schneidkante versehen ist. Diese grenzt an eine Erhebung, die eine quer zur Schneidkante zu messende Breite aufweist, die größer ist als die in gleicher Richtung zu messende Breite der Schneidkante. Dadurch kann die Schneidkante besonders schmal gestaltet werden, wodurch ein symmetrischer Schnitt in der Nähe des Scheitels, der auf dem Greifer aufgenommenen Schlinge zu erreichen ist. Die an die Schneidkante grenzende Erhebung weist jedoch eine größere Breite als die Schneidkante auf, so dass dort anlaufende Fäden, auch wenn sie sich im Arbeitsprozess gegen die Erhebung spannen, ohne Einwirkung des Schneidmessers nicht aufgeschnitten werden. Vorzugsweise weist die Erhebung keine mit dem Faden in Berührung kommende scharfe Kante auf.

This object is achieved in the loop taker according to claim 1:

• The loop taker according to the invention has a gripper finger, which is provided on its underside with a cutting edge. This adjoins a survey, which has a width to be measured transversely to the cutting edge, which is greater than the width of the cutting edge to be measured in the same direction. As a result, the cutting edge can be made particularly narrow, whereby a symmetrical cut in the vicinity of the apex, which can be reached on the gripper recorded loop. However, the adjacent to the cutting edge survey has a greater width than the cutting edge, so that there starting threads, even if they stretch in the working process against the survey, are not cut without the action of the cutting blade. Preferably, the survey has no sharp edge coming into contact with the thread.

At the free end of the gripper finger, a hook may be provided. This serves to receive loops and the acquisition of the same from a tufting needle. The hook can through be formed downwardly angled portion of the gripper finger.

The loop taker typically has two side surfaces and an upper and a lower narrow side therebetween. The side surfaces are those surfaces along which the legs of recorded loops along. The lower narrow side is the side facing away from the carrier material of the tufted goods to be produced. The upper narrow side, however, is the side that faces the substrate, which is also referred to as backing. These direction labels apply regardless of the orientation to the viewer. The term "above" generally refers to the backing-facing side, "upward" refers to the direction of the backing. The term "bottom" generally refers to the side facing away from the backing, "down" the direction away from the backing.

The side surfaces may be aligned parallel to each other. It is also possible to taper the gripper finger over its entire length or over part of it to its free end, so that the side surfaces are at an acute angle to each other. Preferably, the side surfaces except for said recess and a possible attached to one or both side surfaces elevation are flat. On the hook of the gripper finger, they can run into each other at an acute angle and / or turn into a rounding.

The gripper finger is preferably provided with a recess which is sunk into a side surface and passes through at least the lower narrow side. It remains from the narrow side only a narrow bordered by a sharp edge area area left. This area is called Designated "cutting edge". Between the cutting edge and the adjacent side surface, a sharp edge is formed at which the loop is separated by the associated knife. The recess is adjacent to the cutting edge. The cutting edge may extend beyond the recess in one or both of its ends. Conversely, it is also possible that the recess extends beyond the cutting edge at one or both of its ends.

Preferably, the cutting edge is straight. However, it can also be corrugated or otherwise profiled as needed. However, it is preferably in a plane in which also lies that side surface of the gripper finger, which is adjacent to the sharp edge of the cutting edge. The cutting edge may be oriented parallel to the upper narrow side of the gripper finger or at an acute angle thereto.

The elevation bordering the cutting edge may be formed by a step protruding from the cutting edge, which is arranged on the lower narrow side of the gripper finger. The survey may have the existing at this point width of the gripper finger. The width is to be measured as the distance between the side surfaces. The survey thus protrudes in this case only down beyond the cutting edge and is flush with the side surfaces. On its side facing the hook, the elevation may have a sliding ramp surface, so that a loop catching space is formed between the hook and the sliding ramp surface.

However, the survey may alternatively or additionally also extend over one of the side surfaces or both side surfaces. Also in this case, the survey is preferably located at that end of the cutting edge, which is the free end facing the gripper finger. The recess may extend into a lateral elevation. The survey thus formed prevents slippage of the sling from the cutting edge and an unclean cutting or cutting the same.

• Figur 1 einen Schlingengreifer mit angedeuteten Schlingen und zugeordnetem Messer, in Seitenansicht und Prinzipdarstellung.
• Figur 2 den Schlingengreifer nach Figur 1, gesehen von unten.
• Figur 3 den Schlingengreifer nach Figur 1 und 2, in einer perspektivischen Ansicht.
• Figur 4 eine abgewandelte Ausführungsform eines Schlingengreifers in einer Ansicht von unten entsprechende Figur 2 und
• Figur 5 den abgewandelten Schlingengreifer nach Figur 4, in einer Perspektivdarstellung.

Further details of advantageous embodiments of the invention are the subject of the drawing, the description or claims. Show it:

• FIG. 1 a loop grab with indicated loops and associated knife, in side view and schematic representation.
• FIG. 2 the looper FIG. 1 , seen from below.
• FIG. 3 the looper FIGS. 1 and 2 in a perspective view.
• FIG. 4 a modified embodiment of a loop taker in a view from below corresponding FIG. 2 and
• FIG. 5 the modified loop grab after FIG. 4 in a perspective view.

In FIG. 1 For example, a loop taker 10 of an otherwise not further illustrated tufting machine is shown in schematic form. The loop taker 10 is one of a larger number of loop takers held together on a bar of a tufting machine to be moved in unison. Each loop taker 10 serves to receive loops 11, 12, 13 of tufting thread pierced by a backing material called a "backing" to form a pile. The backing and associated tufting needle are in FIG. 1 not shown. The loop taker 10 is designed for the production of Schneidflor. The loop taker 10 is associated with a knife 14, which serves to cut the recorded loops 11 to 13. To this end, the knife 14 is moved up and down (up and down) relative to the loop taker 10 to cut open the loops 13, 14 near its apex so that legs of substantially equal length are formed.

The loop taker 10 is formed of flat material and in FIG. 2 in addition to FIG. 1 illustrated in a view from below. As can be seen from both figures, the loop taker 10 has a gripper finger 15 which extends from a holding end 16 to a free end 17. The holding end 16 serves to attach the loop taker 10 to the bar. The free end 17 serves to remove loops from a tufting needle.

The loop taker 10 has two side surfaces 18, 19, which may be formed, for example, as flat sides and in particular as flat surfaces. The side surfaces 18, 19 are those surfaces on which slide the legs of the loops 11 to 13 along. They are in use substantially perpendicular to the backing and substantially parallel to the flat blade 14. In terms of area much smaller are an upper, the backing facing narrow side 20 and a lower of the Backing turned away narrow side 21. At the transition from the gripper finger 15 to the holding end 16, the lower narrow side 21 on a step 22 which has such a size that no loop beyond this step 22 can fall on the holding end 16. The step 22 is substantially perpendicular to the longitudinal direction L of the gripper finger 15.

The gripper finger 15 merges at its free end 17 into a wedge shape in order to be able to reliably receive loops, such as the loop 11. Otherwise, the side surfaces, as mentioned, preferably parallel to each other both on the gripper finger 15 as well as on the holding end 16. However, it is also possible to orient the side surfaces as a whole, or for example starting from the step 22 at an acute angle to each other, so that the gripper finger 15 slims down from its holding end to its free end 17. Further modifications are possible. For example, the side surfaces 18, 19 may be slightly cambered or arched.

In the loop taker 10 according to the invention, the lower narrow side 21 is formed in a special way. A side surface 19 passing through recess 23 is open to the underside of the gripper finger 15 and thus also passes through the lower narrow side 21. Opposite, a sharp edge 24 is formed at the bottom of the side surface 18. The adjoining the sharp edge 24 portion of the side surface 18 is preferably flat and forms a knife sliding surface for the knife 14. The knife slide and the sharp edge 24 may be formed on the example consisting of steel body of the one-piece gripper finger 15. However, the gripper finger can also have an inlay, for example a carbide insert, to form the sharp edge 24 and the sliding surface. This sits in a formed in the side surface 18 flat pocket and is in this form-fitting by suitable means and / or secured materially. It can be soldered to the gripper finger 15, welded, glued and / or caulked or additionally or additionally attached. Such an inlay is not illustrated in the figures. In any case, the thickness of the inlay is less than the thickness of the gripper finger 15 to allow the formation of the recess 23.

From the narrow side 21 remains only a reduced, in FIG. 2 hatched area shown remaining, which is referred to below as the cutting edge 25. The cutting edge 25 is bounded on the side surface 19 side by the recess 23 and on the side surface 18 side by the sharp edge 24. Toward the holding end 16, the cutting edge 25 is delimited by the step 22. Towards the free end 17, the cutting edge 25 is delimited by a preferably blunt-nosed elevation 26, which extends downwards from the lower narrow side 21. The term "down" here denotes a direction R, which is oriented substantially at right angles to the longitudinal direction L and thus at right angles to the backing. The direction R is parallel to the side surfaces 18, 19.

The elevation 26 adjoins the cutting edge 25 with a step 27. Preferably, the step 27 is oriented substantially at right angles to the cutting edge 25. The step 27 preferably transitions in a curve into a slide ramp surface 28, which is preferably longer than the surface of the step 27. The slide ramp surface 28 is preferably oriented at an acute angle to the longitudinal direction L. It is also preferably oriented at an acute angle to the cutting edge 25. The cutting edge 25 is preferably oriented parallel to the longitudinal direction L. The slide ramp surface 28 may define a loop trap space 30 with a hook 29 formed at the free end of the gripper finger 15 as projecting downwardly. This serves to collect the later in the Cutting space 31 to be transferred loops 12, 13. The cutting space 31 is bounded below the cutting edge 25 by the steps 22, 27.

As can be seen in particular FIG. 2 results in the elevation 26 from one side surface 18 to the other side surface 19. It therefore has a width B which is greater than the width S of the cutting edge. As the width S of the cutting edge is the smallest distance of the recess 23 from the side surface 18 and thus to understand the smallest width, which has formed as a narrow strip cutting edge 25. The circumstances are from the FIGS. 2 and 3 to see. Preferably, the width S of the cutting edge 25 is less than half the width B of the elevation 26th

• In Betrieb vollführt der Schlingengreifer 10 eine schwingende hin- und hergehende Bewegung in Längsrichtung L. Dieser Bewegung kann eine zusätzliche Schwenkbewegung überlagert sein, wobei der in Figur 1 ersichtliche Schlingengreifer 10 jeweils nach links schwingt, um eine von einer Tuftingnadel durch das Backing gestochene Schlinge aufzunehmen und nach Rückzug der Nadel wie die Schlinge 11 zu halten. Das beim Tuftingprozess schrittweise nach rechts bewegte Backing nimmt entsprechende Schlingen mit, bis sie wie die Schlingen 12, 13, die Gleitrampenfläche 28 passiert haben und auf der Schneidkante 25 zu liegen kommen. Das rhythmisch auf und ab bewegte Messer 14 schneidet sie hier mit seiner Schneidkante 32 auf.

The loop grab 10 described so far operates as follows:

• In operation, the loop taker 10 performs a swinging reciprocating motion in the longitudinal direction L. This movement may be superimposed on an additional pivoting movement, wherein the in FIG. 1 swinging looper 10 each swinging to the left to pick up a loop pierced by a tufting needle through the backing and to hold it after retraction of the needle as the loop 11. The during the tufting process gradually moved to the right backing takes appropriate loops with them until they like the slings 12, 13, have passed the Gleitrampenfläche 28 and come to rest on the cutting edge 25. The knife 14, which moves rhythmically up and down, cuts it here with its cutting edge 32.

The loops 11, 12, 13 are preferably made of a highly lubricious, for example non-stick coated Material that offers high resistance to cutting, as is the case with polyester, for example. However, the loop taker according to the invention is also suitable for unproblematic yarns, such as wool, cotton or other natural fibers or synthetic fibers.

When the cutting edge 32 acts on the loops 12, 13, they can not leave the cutting space 31. The step 27 prevents slipping and dragging or other distortion of the loops 12, 13 effectively. At the same time, due to its large width B, the step 27 provides a planar contact for the lower U-shaped sections of the loops 12, 13, so that these, even if they are pressed firmly to the step 27, no cuts or tears. This does not happen even if the step 27 merges into the side surfaces 18, 19 with a very small radius of curvature. If necessary, however, the transition from the step 27 to the side surfaces 18, 19 may also be rounded.

The elevation 26 does not necessarily have to be arranged on the lower narrow side 21. Alternatively or additionally, it may be arranged on one of the side surfaces 18, 19 or on both side surfaces. FIGS. 4 and 5 illustrate an example in which the elevation 26 is arranged both on the narrow side 21 and also occupies a part of the side surface 19. The above to the FIGS. 1 to 3 given description applies accordingly. In addition, it should be noted that the elevation 26, insofar as it is provided on the side surface 19, may have a step surface 33 on the side facing the recess 23, which may be penetrated by the recess 23. The latter measure can be used to hold the cutting edge 25 relatively close to the step 27 to produce when cutting the loops 12, 13 as long as possible legs. The step surface 33 is preferably in a rounding in a sliding surface 34, which at an acute angle to the other side surface 19th stands. The length of the sliding surface 34 may coincide with the length of the sliding ramp surface 28 or, as it is FIG. 5 illustrated, be set differently. The step surface 33 may be perpendicular to the side surface 19 or according to FIG. 4 be oriented at a different angle, for example, at an obtuse angle to this.

If the elevation 26 is arranged on a side surface 18 and / or 19, it can be dispensed with, and at the same time provided on the narrow side 21. In this case, this width is greater than the width S, preferably at least twice as large as the width S, even more preferably at least three times as large as the width B is here from the side surface 18 up to the laterally projecting position of the lateral elevation the width S. This also applies to embodiments in which the elevation 26 occupies both the narrow side 21 and a portion of the side surface 19.

However, an embodiment according to one of the figures is preferred. It should be noted that both on the narrow side 21 as well as on the side surface 18 and / or the side surface 19 instead of a single survey 28, two or more such surveys may be provided, which are arranged staggered, for example, in the longitudinal direction to each one Slipping back slipped loops when moving the tufting gripper and backing. However, it is essential to prevent evasion or slippage of the loops 12, 13 when cutting through the blunt, non-cutting step 27 or step surface 33.

The loop taker 10 according to the invention makes it possible to produce tufted goods with materials which, for example, are coated with a friction-reducing coating in order to form a dirt-repellent, perceptibly soft surface. It shows that such materials are problematic in the manufacture of cut pile and occasionally uneven pile heights occur. The loop taker 10 according to the invention is provided following its narrow cutting edge 25 with a comparatively wider step 27 or 33, which prevent slippage of the loop without cutting it. LIST OF REFERENCE NUMBERS 10 looper 11, 12, 13 wrap 14 knife 15 gripper fingers 16 holding end 17 Free end 18, 19 faces 20 Upper narrow side 21 Lower narrow side 22 step L longitudinal direction 23 recess 24 Sharp edge 25 cutting edge 26 survey R Direction "down" 27 step 28 Tramp sliding surface 29 hook 30 Snare trap area B Width of the survey 26 S Width of the cutting edge 25 31 cutting room 32 Cutting edge of the knife 14 33 step surface 34 sliding surface

Claims (12)

1. Loop gripper (10) for a tufting machine, in particular for producing cut pile,
   wherein the loop gripper (10) has a gripper finger (15) which extends from a holding end (16) to a free end (17) and on its underside (21) is provided with a cutting edge (25), and
   wherein a protrusion (26) is arranged adjacent to the cutting edge (25) in the direction towards the free end (17),
   wherein a hook (29) is provided on the free end (17) of the gripper finger (15), and
   the protrusion (26) bordering the cutting edge (25) is formed by a step (27) which protrudes from the cutting edge (25) and is arranged on a narrow side (21) of the gripper finger (15),
   characterised in that
   the protrusion (26) has a width measured transversely to the cutting edge (25) which is greater than the width of the cutting edge (25) measured in the same direction,
   the step (27) is formed by a shoulder which has a slide ramp face (28) arranged obliquely to the cutting edge (25), and
   a loop capture space (30) is established between the slide ramp face (28) and the hook (29).
2. Loop gripper according to the preceding claim, characterised in that the gripper finger (15) has two side faces (18, 19) and between them an upper and a lower narrow side (20, 21), wherein the cutting edge (25) is formed between one of the side faces (18, 19) and the lower narrow side (21).
3. Loop gripper according to any of the preceding claims, characterised in that a side face (18) adjoining the cutting edge (25) has a flat face portion extending away from the cutting edge (25).
4. Loop gripper according to claim 2 or 3, characterised in that the gripper finger (15) is provided with a recess (23) which is cut into a side face (19) and passes through a narrow side (21).
5. Loop gripper according to claim 4, characterised in that the recess (23) is adjacent to the cutting edge (25).
6. Loop gripper according to any of the preceding claims, characterised in that the cutting edge (25) is formed straight.
7. Loop gripper according to any of the preceding claims, characterised in that the cutting edge (25) is formed profiled.
8. Loop gripper according to any of the preceding claims, characterised in that the protrusion (26) bordering the cutting edge (25) is formed by the step (27) which protrudes from the cutting edge (25) and is arranged on a narrow side (21) of the gripper finger (15).
9. Loop gripper according to claim 4, characterised in that the protrusion (26) is arranged bordering the recess (23).
10. Loop gripper according to claim 4, characterised in that the protrusion has a step face (33) which faces the recess (23).
11. Loop gripper according to any of claims 8 to 10, characterised in that the recess (23) is cut into the protrusion (26).
12. Loop gripper (10) for a tufting machine, in particular for producing cut pile,
    wherein the loop gripper (10) has a gripper finger (15) which extends from a holding end (16) to a free end (17), has side faces (18, 19), and on its underside (21) is provided with a cutting edge (25), and
    wherein a protrusion (26) is arranged adjacent to the cutting edge (25) in the direction towards the free end (17),
    wherein the protrusion (26) has a width measured transversely to the cutting edge (25) which is greater than the width of the cutting edge (25) measured in the same direction,
    characterised in that
    the protrusion (26) is arranged on one of the two side faces (18, 19) or on both, and has a step face (33) facing the recess (23).

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