EP1127973B1 - Sewing needle for multidirectional sewing - Google Patents

Description

The invention relates to a needle for a sewing machine.

Sewing machines usually have a needle that has an eye near its tip through which a Upper thread is guided. The needle sticks in when sewing rapid sequence through the sewing material (textile fabric), taking the needle through the gradual transport of the sewing material are spaced apart stitch holes. The upper thread is passed from tap hole to tap hole, going both forward and backward through the eye while sliding over an edge of the same. If the The direction of transport of the sewing material is defined Needle a specified direction of work and the sewing material is in a fixed direction, usually across the eye, transported. However, it turns out that at Sewing machines that transport the material in different ways Allow directions, such as forward / backward or in several different directions (multidirectional), the seam quality depends on the direction of sewing and / or the twisting of the thread. This is often undesirable.

From utility model DE-A-8632106.4 is e.g. a Known tufting needle. This points towards the Elongated eye lying on the needle axis, that on both Ends have a curved upper or lower eye edge. On the spout is straight. In top view, i.e. looking in the eye axis is the tufting needle asymmetrical. Connects on the outlet side the eye a curved thread groove.

Such a tufting needle has a preferred working direction on.

In contrast, US-A-3,986,468 is a symmetrical one Needle known for a sewing machine. The needle points in close to its tip a cross across the needle body extending eye, which is bounded by two eye walls becomes. Both eye walls have both on their top and also straight edges on their underside, i.e. the edges of the side walls each extend along a straight line from the shaft-side eye end to the tip end of the eye.

Such sewing needles, although symmetrical are different behaviors when sewing forward and when sewing twisted threads backwards.

DE-A-38 10 481 describes a hard metal sewing machine needle known, which has a shaft with a transverse Has eye. At the shaft end of the A bead-like elevation is provided for Öhrs. The edges of the eye are on the thread outlet side in side view just trained.

Such sewing needles show quality differences in Sew forward and when sewing backward when twisted Material is used.

A tufting needle is known from EP-A-0 163 278, whose eye rim both on its tip-sided End as well as one at its shaft end Has survey. In between, it runs along one Straight.

Tufting needles are used, for example, to make carpets. They are not suitable as sewing machine needles.

Based on this, it is an object of the invention to To create a needle for a sewing machine with which the Reduce quality differences between seams, which are generated in different sewing directions.

This task is solved with a needle that the Features of claim 1.

The needle according to the invention has an eye that extends across the needle body. Under "across" will both have a right-angled alignment of the eye the longitudinal central axis of the needle body, as well as an inclined Alignment understood at an acute angle to this. The eye is delimited by two eye walls that join the outlet side of the eye, i.e. on the side from which starting the thread extends to the sewing material, lowered are. In other words, the edges of the eye walls are curved towards the back of the needle or are otherwise shaped. The eye walls, which act as side walls of a thread outlet channel can continue, thus extend between two places regarding the needle thickness each represent a local survey. In this way the lowered eye walls allow a twisted one Thread running sideways across the eye wall across the eye, without the thread twisting when running over the Eye wall is changed to a greater extent. By the diminished Influencing the thread twist becomes the basis created for that in different sewing directions Preserve seams with at least approximately the same quality can be. For example. the thread receives when sewing forward and no significantly different when sewing in reverse Twisting when crossing the eye walls.

By lowering the contour in the eye area below an imaginary connecting line between the shaft side Eye end and a tip-side neighboring Elevation, the friction between the thread and the Edge of the eye wall can be reduced. The decrease in Friction is therefore independent of the angle that the thread with the needle, less thread interference result. He is accordingly less or twisted. This results in an improved seam appearance and an improved quality of the sewing material. Moreover can occur with conventional needles in extreme cases Effects are avoided. If the twist becomes one twisted thread too much when sewing, can the loop formation are impaired. Will be a thread twisted or twisted and in this state by the Stitched material, it can become when the needle is withdrawn twist or swirl without proper Train the loop. This would have skipped stitches and possible Thread breaks result. With the new contour of the invention Such extreme error conditions can be needle avoid. This applies in particular to multidirectional Sew the material automatically in all possible directions, but at least in two directions can be transported. The one in accordance with the invention Needle effect of less influencing the However, twisting can also be important for sewing machines, that only sew in one direction. The new needle enables the use of upper threads with different Twisting, e.g. right-hand twisted threads or left-hand twisted threads, the influence of the direction of twisting on the seam quality goes back clearly and in becomes meaningless in most cases.

The eye walls are preferably of stepless design and concavely curved on the eye outlet side. This Curvature of the upper edges of the eye walls on the eye outlet side supports the above uniform Thread run regardless of the sewing direction and enables also a high sewing speed due to the overall reduced eye height and the resulting slowly opening the tap hole.

In a preferred embodiment the needle is a thread gutter following the end of the eye at the outlet trained that towards the top extends, with the eye walls in the side walls of the Pass over the thread gutter. The result is a good one Thread guidance and in particular a good support of the Thread when looping. This is the moment when the needle has inserted the thread through the material and their return stroke begins or goes through.

A concave arcuate curvature of the side walls enables the generous rounding of their respective Edges or the flattening transverse to the direction of the eye. In both In cases, the thread can be largely undisturbed over the concerned Edge run, taking the angle, the individual Include strands or filaments of the thread with the eye wall, is of minor importance. this applies especially for the design with a flattened edge.

In an advantageous embodiment, the outlet side Thread trough parallel to the longitudinal extent the needle aligned. The needle has no through the thread groove predetermined preferred working direction, what accommodates the multidirectional usability.

The needle is also preferably one Longitudinal median plane formed symmetrically. The two eye walls are then mirror-symmetrical to each other. This also comes from the multidirectional work opportunities towards the sewing needle.

The eye is preferably adjacent to the shaft of the needle a groove is arranged, which the gripper at Allow enough space for sewing. In a preferred one Embodiment is the shaft in the area between the tip of the needle and the fillet flattened overall and preferably only points between the eye and the fillet reaches its maximum shaft height at the eye. This has advantages in opening the tap hole and with regard to the thread running in different working directions.

It has been shown that the contour is lowered the eye walls is particularly effective when the distance the lowest point of descent to the central axis is approximately 25% of the nominal shaft diameter.

If necessary, the eye of the needle can also be turned on be flattened on the thread entry side if additional Effects are to be brought about. However, it is considered appropriate viewed the edges of a thread infeed channel over to continue the eye straight. This makes a good one Protection of the thread on the inlet side of the eye.

Fig. 1 eine erfindungsgemäße Nadel in abschnittsweise längsgeschnittener Darstellung,

Fig. 2 die Nadel nach Figur 1, in einem anderen Maßstab und in ausschnittsweiser längsgeschnittener Darstellung,

Fig. 3 die Nadel nach Figur 1, in einer ausschnittsweisen Draufsicht,

Fig. 4 die Nadel nach Figur 2, geschnitten entlang der Linie IV-IV in einem anderen Maßstab,

Fig. 5 die Nadel nach Figur 2 oder 3, geschnitten entlang der Linie V-V in einem anderen Maßstab,

Fig. 6a bis Fig. 6d die Nadel nach Figur 1, beim Vorwärtsnähen in verschiedenen Phasen des Einstichs, in schematisierter Prinzipdarstellung, und

Fig. 7a bis Fig. 7d die Nadel nach Figur 1, beim Rückwärtsnähen in verschiedenen Phasen des Einstechens, in schematisierter Darstellung.

Advantageous details of embodiments of the invention are the subject of dependent claims. Further details emerge from the drawing or the description. An exemplary embodiment of the invention is illustrated in the drawing. Show it:

1 shows a needle according to the invention in sections in longitudinal section,

2 shows the needle according to FIG. 1, on a different scale and in a partial longitudinal section,

3 shows the needle according to FIG. 1, in a partial plan view,

4 shows the needle according to FIG. 2, cut along the line IV-IV on a different scale,

5 shows the needle according to FIG. 2 or 3, cut along the line VV on a different scale,

6a to 6d the needle according to FIG. 1, when sewing forward in different phases of the puncture, in a schematic basic illustration, and

Fig. 7a to Fig. 7d, the needle of Figure 1, when sewing backwards in different phases of the piercing, in a schematic representation.

In Figure 1, a needle 1 is illustrated, the Shank 2 (needle body) from one intended for clamping Clamping part 3 to a tip 4 along one Longitudinal central axis 5 extends. The shaft 2 is preferred stretched, i.e. just trained. If necessary, However, it can also be designed in another way, for example cranked his. The longitudinal central axis 5 is through the tip 4 fixed and agrees with the longitudinal direction of the shaft 2 match.

Near the tip 4 is the shaft 2 with one Provide eye 6 that leads across the shaft 2. The Eye 6 can, as can be seen from Figure 3, by a oblong or oval opening, through a round hole or be formed by openings of another shape. The relevant opening, which forms the eye 6, has an in central axis not further illustrated in the figures or opening axis, which the longitudinal central axis 5 preferably cuts and at right angles or at an acute angle is inclined to this. In all cases leads the eye 6 across the shaft 2. The eye 6 is with respect to that defined by the longitudinal central axis 5 Longitudinal direction on the side remote from the tip 4 through a first eye end 7 and towards the tip 4 lying side bounded by a second eye end 8. Both eye ends 7, 8 are preferably more or less rounded and without sharp edges. In which Eye 7 reaches the shaft 2 of the needle 1 at one Position 9 (FIG. 2) a height above the needle back 10, which corresponds to approximately 87% of the nominal size of needle 1 and between the tip 4 and an adjoining position 9 Fillet 11 a highest elevation, i.e. maximum shaft thickness. In other embodiments can the height of the shaft 2 at the point 9, however also be determined otherwise.

Extend between the point 9 and the second eye end 8 3 seen in plan view eye walls 14, 15, which are mirror-symmetrical to one another are. Between the second eye end 8 and the tip 4 go the eye walls 14, 15 in side walls 16, 17 one thread groove 18 on the outlet side for thread guidance, which is arranged parallel to the longitudinal central axis 5.

As can be seen in particular from FIGS. 1 and 2, have the eye walls 14, 15 and the side walls 16, 17th each have an upper edge 19a, 19b, 20a, 20b, which the Defines the contour of the eye 6 on the thread outlet side. The Edges 19a, 20a, 19b, 20b form a closed saddle-shaped Annular surface. The one defined by the margin 19, 20 Contour to be seen transversely to the eye 6 Does not touch an imaginary line 21, the 9th connects to a point 22 at which the thread groove 18th ends. This imaginary line or straight line 21 is preferred at a positive acute angle to the longitudinal central axis 5 oriented. In the illustrated embodiment it is about 5 °. The paragraph and stepless as well Lay edges 19, 20 that merge into one another without kinks preferably a bow stuck in its middle Area approximates to the longitudinal central axis 5. The greatest approximation to the longitudinal central axis 5 is preferred approximately in the area of the tip-side (second) eye end 8 reached. Here the distance to the longitudinal central axis is 5 preferably only 25% of the nominal shaft diameter Or less.

The thread groove 18 is in the present embodiment kept relatively flat. This means that the Side walls 16, 17 are significantly lower than the width of the eye 6. The height of the side walls 16, 17 is thus preferably much less than the thickness of the thickest through the eye 6 feasible thread.

As can be seen in particular from FIG. 4, the Eye walls 14, 15 on the upper in Figures 1, 2 and 4 Side, i.e. on the thread outlet side by the edge 19a, 19b is fixed, sliding surfaces 24, 25 on the transverse to the opening direction 26 indicated in FIG. 4 of the eye 6 is at least partially straight are. At the respective transitions to the inner wall of the eye 6 or to the outside of the needle 1, are the Sliding surfaces 24, 25 rounded.

The needle 1 is from the tip 4 to the eye 6 preferably symmetrical. In the further course however, it can deviate from symmetry, such as in particular is apparent from Figures 3 and 5. In the area the fillet 11 can be provided with a lateral bevel 27 be enough space for a sling grab to offer.

On the back of the needle 10 is the fillet 11 away from the side, preferably a thread inlet channel 28 trained up to the eye 6 or over this extends beyond. The thread runner 28 is preferred delimited by straight-edged side walls 29, 30, the height of the side walls 29, 30 is dimensioned so that a thread running to the eye 6 completely from the Thread inlet channel 28 is added or at most slightly protrudes from the thread inlet channel 28. How FIG. 1 illustrates the thread inlet channel 28 also have a graduated height, the depth or the height of the thread inlet channel to the eye 6 reduced.

The needle 1 described so far works like follows:

Reference is first made to FIGS. 6a to 6d, the needle 1 in different phases when sewing forward illustrate. The needle 1 is in figure 6a above a hold-down 35, which with a a thread 31 to be sewn textile fabric 32 rests. The thread 31 stretches from a point 33, through the last stitch hole and the last stitch knot is determined to the eye 6 of the needle 1, which moved to the textile fabric 32. The thread 31 is kept taut. It is twisted on the left (z-twisted), the twisting in Figures 6a to 6d is indicated in the drawing. The thread 31 is on the Sliding surface 24, with the individual filaments or strands of the thread 31 longitudinally approximately transversely to the longitudinal central axis 5 run over the edges of the sliding surface 24. An influence the twist is therefore relative from the outset low.

When the needle moves in the figures 6b and 6c is indicated, the thread 31 through the eye 6 tightened to the extent that the distance between the point 33 and the eye 6 reduced. By lowering the eye wall 14 and the flat or generous Rounded formation of the sliding surface 24 can this process without additional twisting and without swirl feed of thread 31 run off. This is shown in FIG. 6a to 6d shown and relatively constant pitch angle the twist.

Although the conditions when sewing in reverse are basically are different, the twist remains largely here unchanged. This is shown in FIGS. 7a to 7d out. Again, a thread 31 is used, the has the same twist as that used for forward sewing Thread 31. However, the textile fabric not as in Figures 6a to 6d with respect to the needle 1 moved to the right but to the left. This is in the Figures 6 and 7 each indicated by an arrow T. The position 33 with the last stitch knot is thus moved away from the needle 1 such that the thread 31 over the eye wall 15 and the sliding surface 25 runs. The twist is such that the individual filaments or strands of the thread 31 parallel or at an acute angle to the Longitudinal central axis 5 over the sliding surface 25 and its edges to run. Due to the flattened design of the sliding surface 25 and its rounded edges engage the eye wall 15 but not in the twisting of the thread 31 and does not change them. In particular, the Twisting (when tightening the thread) not pushed together, so the thread 31 has no additional twist receives. This way, both when sewing forward as well as when sewing in reverse the same seam qualities or achieved at least approximately the same seam quality. In addition, the seam quality is independent of the direction of twisting of thread 31 in both forward and also when sewing in reverse. Beyond that too Seams with lateral movement of the material (textile fabric 32) in the same or at least almost the same Achieve quality.

The needle 1 is intended for sewing machines that in at least two, but preferably several directions can sew. For this purpose, the needle 1 has a novel geometry on. It is in the area of the eye on the fillet side towards the top with a bilateral depression the eye edge or the channel edge of the outlet side Provide thread guide groove. The full Shaft height at the eye only in the area between the fillet end and the beginning of the eye reached. The depth of the depression depends of the needle size and can be determined as required. The lengths of the lowered eye edges / gutter edges depend on the needle geometry. The length of the eye ridges is preferably chosen so that the outlet the straight thread outlet channel is retained.

Claims (11)

1. Needle (1) for a sewing machine,
   with a needle body (2), which has a point (4) at one end and a clamp part (3) at its opposite end, wherein the point (4) defines a longitudinal central axis (5), which corresponds to the longitudinal direction of the blade (2),
   with an eye (6) extending transversely through the needle body (2), said eye being disposed in the vicinity of the point (4) and defined between two eye walls (14, 15), with edges (19, 20), which define the contour of the eye (6) on its thread exit side, wherein the edges extend on the exit side from a blade-side eye end (7) to an opposite point-side eye end (8), wherein the contour, at least in the eye region, runs below an imaginary direct joining line (21) between the blade-side eye end (7) and a point-side raised section (22),
   characterised in that
   the edges (19, 20) define an arc, which approaches the longitudinal central axis (5) in its central region.
2. Needle according to Claim 1, characterised in that the edges (19a, 19b) of the eye walls (14, 15) have a concave curvature.
3. Needle according to Claim 1, characterised in that a thread groove (18), which extends towards the point (4), is provided in the adjoining area to the eye (6) on the exit side on the needle (1), and that at the eye end (8) on the point side, the eye walls (14, 15) merge into side walls (16, 17) of the thread groove (18).
4. Needle according to Claim 3, characterised in that the edges (19a, 19b) of the eye walls (14, 15) and the edges (20a, 20b) of the side walls (16, 17) of the adjoining thread groove (18) are curved in an arc shape.
5. Needle according to Claim 3, characterised in that the thread groove (18) on the exit side is oriented parallel to the longitudinal extension of the needle (1).
6. Needle according to Claim 1, characterised in that the eye walls (14, 15) are configured symmetrically to one another relative to an imaginary longitudinal central axis centrally dividing the eye (6).
7. Needle according to Claim 1, characterised in that the side walls (14, 15) of the eye (6) are flattened in transverse direction on the exit side of the eye (6).
8. Needle according to Claim 1, characterised in that the side walls (14, 15) of the eye (6) have rounded edges on the exit side of the eye (6).
9. Needle according to Claim 1, characterised in that in the section between the point (4) and a furrow (11), only between the eye (6) and the furrow (11), the needle body (2) of the needle (1) has a height, which corresponds to 80% to 90%, preferably 87%, of the nominal height of the blade (2).
10. Needle according to Claim 1, characterised in that at at least one location (8), the eye walls (14, 15) are at a distance of about 25% of the nominal height of the blade from the longitudinal central axis (5) at their lowest point as a result of the exit-side downward slope of their edges (19).
11. Needle according to Claim 1, characterised in that on the feed side, the eye walls (14, 15) are defined by edges, which are straight and preferably extend as a straight extension of the edges of side walls (29, 30), which define a thread feed groove (28).

Images