EP1052324A2 - Sewing machine needle with offset eye lips - Google Patents

Abstract

The sewing machine needle (1) has an eye (11) which is defined by two spaced straps (12,14) offset against each other across needle center axis (4). The eye straps (12,14) are rounded, with a rounding radius pref. equal to one-half the thickness of the eye straps (12,14). offset gap between the eye straps (12,14) is at least 40% of the nominal needle thickness, and pref. 50%. The needle eye straps (12,14) each have a transit zone (15,18) between their rounded ends and a base surface (16,17) towards the sewing thread, on the center axis (4). The passage through the needle eye (11) is a straight line past the surfaces (16,17) on the thread side, at an acute angle of ≤ 20 degrees to the center axis (4). At least one eye strap surface (16,17), and pref. both, is concave toward the sewing thread. The length of the needle eye (11), along the center axis (4), is less than twice the nominal needle thickness and pref. 1.0-1.1 times. Each eye strap (12,14) is defined by a thread groove (21,32) at the surface on the thread side. The eye walls have inner surfaces, with an axial sections between them at different angles. The needle (1) height, measured at the eye ( at right angles to the center axis (4), is less than the needle thickness. The eye strap (12), between the eye and the needle clamping section, has walls which do not project over the sides of the strap (12).

Description

The invention relates to a sewing machine needle, in particular for high-speed sewing machines.

Stitches of 5000 stitches / min and more are today the rule for industrial sewing machines. With certain Applications are even up to 8000 stitches / min achieved more.

When the needle is inserted into the material, it opens a stitch hole and pulls the thread (sewing thread) into the stitch hole on. If the number of stitches is very high, the opening of the At most a very short period of time about 0.5 ms or less. The taphole opening time is the duration from the first touch of the sewing material through the needle tip up to the eye passage. Through the almost explosive opening of the tap hole there is high frictional force between the sewing machine needle and the sewing material. Therefore, relatively large puncture forces can occur what is required for the needle insertion required energy requirements increased.

Due to the high frictional force between the needle and the Sewing material generates heat when the taphole is opened Material can be thermally damaged. E.g. can synthetic fibers be melted or melted in the puncture area. Fibers or fiber associations can also by the explosive opening of the tap hole mechanically damaged become. Another consequence are common ones Sewing thread breaks.

In addition, the sewing production, depending on the sewing material, by melting laminates and coatings as well are hindered by paint or equipment components. These problems can be greatly reduced Seam quality and impaired wearing properties ready-made textiles.

From this derives the effort to close stitch holes downsize. However, this takes place in most cases specified thread thickness and the size of the for guiding of the sewing thread required sewing machine needles Border. A certain sewing thread thickness sets a certain one Minimum needle size ahead. In addition, the size of the The eye of the needle is analogous to the needle size.

Another problem with sewing needles is especially at higher machine speeds that mechanical stress on the sewing needle. Rotating masses in The sewing machine can cause vibrations that especially on the sewing machine needle clamped on one side impact. Also act on the needle as a result of thread tension and deflection when hitting the sewing machine needle on the material and as a result of operational influences other powers. This in turn leads to the desire sewing machine needles as thick as possible, the have sufficient rigidity. Both demands a sewing machine needle as thin as possible to protect the Material and to avoid excessive needle heating to use and a sewing machine needle as thick as possible use the required stability at high sewing speeds to achieve, contradict each other.

A sewing machine needle is known from US Pat. No. 4,037,641 known with a straight shaft that is near its tip has an eye that runs transversely to its central axis. The eye is in the axial direction by two opposite one another Öhrstege limits, both essentially lie on the central axis of the sewing machine needle. To the Öhr closes in the direction of the clamping part of the Shaft, a thread groove. On the opposite Side of the sewing machine needle is another short one, in In the direction of the groove to be run on the needle tip, which ends flat in the immediate vicinity of the eye. Closes on the same side of the sewing machine needle a groove at the eye in the direction of the clamping part on. The one between the thread gutter and the fillet arranged eye bridge is rounded on the eye side and serves to pull the thread into an open stitch hole.

Due to the approximately central arrangement of the eye bridge in relation the thread runs on the shaft when piercing it Sewing material on one side of the sewing machine needle in the Thread gutter while on the other side of the sewing machine needle essentially takes place in the fillet. The The eye area of the sewing machine needle is transverse to the central axis and dimensioned in the opening direction of the eye that the open hole is relatively large. Surrender the above relationships.

If the sewing machine needle is in a return stroke from the If the sewing material is pulled out, it runs through the eye Thread on an S-curve through the eye. Existing here Friction leads to corresponding forces between the sewing machine needle and the thread and to a corresponding one Warming.

It is an object of the invention, the sewing machine needle to improve with regard to the problem mentioned at the beginning.

This task is solved with a sewing machine needle, which has the features of claim 1:

The sewing machine needle according to the invention has a Essentially just trained shaft. This one has no offset area in which parts of the shaft laterally could protrude beyond its undiminished contour. Thereby it is possible that the penetrating material Sewing machine needle the flanks of the stitch hole created not laterally deflected, which accelerates the Sewing material in the lateral direction and this may result Friction is avoided.

The sewing machine needle according to the invention has two spaced-apart eye bridges that run against the central axis the sewing machine needle. The offset is preferably such that the to the clamping part indicative Öhrsteg a barrier-free transition in the eye releases. It is thus on the side facing away from the thread groove Side of the sewing machine needle arranged. In contrast is towards the tip of the sewing machine needle pointing eye bridge straight to the other side of the eye transferred. It is approximately in the imaginary extension of the thread groove arranged. Overall, these measures enable reduced friction of the thread on the sewing machine needle and reduced friction of the sewing machine needle when piercing the material. The offset of the eye bridges against each other allows a reduction in the amount of Sewing machine needle in the eye area compared to the nominal size the sewing machine needle without any loss in principle the needle stiffness. The height of the sewing machine needle is perpendicular to the central axis and in one through the Eye leading direction measured.

Reducing the friction of the sewing machine needle with the sewing material occurs especially when inserting the sewing machine needle in the sewing material in appearance. On the return stroke the offset of the eye webs enables a low deflection Thread running in the area of the eye, so here again there is no excessive friction.

Overall, the puncture force is lower, resulting in a lower power requirement to drive the sewing machine needle. Besides, that is too emerging needle warming due to decreased Less friction. At the same time, there is a gentle on the material Tap hole opening with high thread protection. The likelihood of skipped stitches and thread breaks is significantly reduced.

In an advantageous embodiment of the invention the eyelets are rounded and free of edges, the rounding of the top, i.e. to the clamping part indicative eye bridge at a desired eye bridge thickness preferably a radius of 50% of the nominal needle size of 20% of the nominal needle size. This leads overall to a good thread run.

The eye bridges are preferably against one another Distance offset transversely to the central axis, the minimum 40% to a maximum of 50% of the nominal needle size. This allows the thread protection in the elongated longitudinal passage of the thread can be optimized through the eye.

The eyelets are preferably about half as thick as the nominal nominal size of the sewing machine needle. Thereby there is both the possibility of a slim design the sewing machine needle in the ear area, as well as one good stability and rigidity.

The tip of the sewing machine needle can be on a central axis lying at the same time approximately in the middle through the eye leads. If necessary, the tip of the sewing machine needle however, they can also be arranged offset with respect to the central axis. Regardless of this, it is expedient to use the eye bridges in this way to order that an imaginary, going through the eye and straight line resting on the inner surfaces of the eye bridges encloses an acute angle with the central axis, which is less than 20 °. The eye bridge offset and at the same time the small acute angle of the so defined, through the eye bridge running tangents allow low friction of the thread on the sewing machine needle, even if the eye is in Axial direction (direction of the central axis) is relatively narrow.

The friction can still be due to a concave design the eye bridges can be reduced.

The sewing machine needle preferably has a relative short eye at which the measured in the axial direction Distance between the eye bridges about one to 1.1 times as much is large, like the nominal needle size. This gives one precise guidance of the thread and can possibly too lead to a reduction in the required penetration depth.

The eye walls preferably have a non-flat face on the eye side Walls open, with the eye walls facing both eye openings diverge. It can also be between the eye walls included angles measured transversely to the central axis vary along the central axis. This favors the The thread runs through the eye and reduces its friction. At the same time the bilateral support of the Stitch interlocking ensures the required thread loop.

In the neighborhood of the eye can on one of the thread gutter side of the sewing machine needle a groove be provided. The fillet preferably goes without a sharp edge in the eye over what the thread guard is useful.

A preferred embodiment of the sewing machine needle has eye walls that do not have the to the clamping part projecting eye bridge. This results in a relatively small needle cross section in the cross area and a comparatively slow opening of the tap hole and a appropriate protection of the sewing material.

Further details of advantageous embodiments the invention is the drawing or the description remove and / or subject of subclaims.

Fig. 1 eine Nähmaschinennadel mit einem gestreckt durch das Öhr laufenden Faden, in längsgeschnittener, ausschnittsweiser und vereinfachter Darstellung,

Fig. 2 die Nähmaschinennadel nach Figur 1, geschnitten entlang der Schnittlinie II-II in Figur 1, ohne Faden,

Fig. 3 die Nähmaschinennadel nach Figur 1, geschnitten entlang der Schnittlinie III-III in Figur 1, ohne Faden

Fig. 4 die Nähmaschinennadel nach Figur 1, mit einem durch das Öhr laufenden Faden beim Einstichvorgang, in längsgeschnittener, schematisierter und ausschnittsweiser Darstellung,

Fig. 5 die Nähmaschinennadel nach Figur 1, mit einem durch das Öhr laufenden Faden, nach dem Einstichvorgang zu Beginn des Rückhubs, in längsgeschnittener, schematisierter und ausschnittsweisen Darstellung, und

Fig. 6 die Nähmaschinennadel nach Figur 1, mit einen durch das Öhr laufenden Faden, beim Rückhub, mit ideal ausgebildeter Fadenschlinge zur Aufnahme durch den Schlingenfänger in längsgeschnittener, schematisierter und ausschnittsweiser Darstellung.

An exemplary embodiment of the invention is illustrated in the drawing. Show it:

1 is a sewing machine needle with a thread stretched through the eye, in a longitudinally cut, cutaway and simplified representation,

2 shows the sewing machine needle according to FIG. 1, cut along the section line II-II in FIG. 1, without thread,

Fig. 3 shows the sewing machine needle of Figure 1, cut along the section line III-III in Figure 1, without thread

4 shows the sewing machine needle according to FIG. 1, with a thread running through the eye during the puncturing process, in a longitudinally sectioned, schematic and partial representation,

5 shows the sewing machine needle according to FIG. 1, with a thread running through the eye, after the puncturing process at the beginning of the return stroke, in a longitudinally sectioned, schematic and partial representation, and

6 shows the sewing machine needle according to FIG. 1, with a thread running through the eye, on the return stroke, with an ideally designed thread loop for reception by the loop catcher in a longitudinally sectioned, schematic and partial representation.

1 shows a sewing machine needle 1, the shaft 2 of which is not illustrated in FIG. 1 and adjoining shaft 2 on the left Clamping part up to a point 3 along a central axis 4 extends. The tip 3 is preferably on the Central axis 4. The shaft 2 is, as illustrated in FIG. 3, on its upper side in the figure 5 and its lower side 6 is substantially flattened. Arranged between the side 5 and the side 6 Side surfaces 7, 8 are convexly curved. The cross section the sewing machine needle 1 is weakened in this area Shaft 2, apart from the convex curvature the side surfaces 7, 8, approximately square. The nominal Needle size is in the shaft area above the fillet in the direction of the clamping part by the diameter of the Sewing machine needle 1 determined.

It is not too far from the tip 3 an eye 11 arranged transversely to the central axis 4 through leads the shaft 2 and this can be seen from Figures 1 and 2 is. The height of the eye 11 is determined by the distance of pages 5 and 6 to each other. In this area (Öhr 11) the sewing machine needle 1 is preferably something weaker than in the un weakened area of the Shaft 2, which is shown on the left in Figure 1. The diminution the thickness of the shaft 2 is in the eye area Embodiment at about 5% to 20%, preferably about 10% in terms of the distance between side 5 and page 6 in the undiminished area.

The eye 11 is designated by the central axis 4 Axial direction limited by two eye webs 12, 14, against the central axis 4 in the direction of the thread guard 21 or groove 34 are offset. On their end facing the eye 11 are the eye webs 12, 14 each rounded approximately semicircular, the radius of curvature each relatively exactly half the thickness of each Öhrstegs 12, 14 corresponds. The in the transverse direction, i.e. in Figure 1 vertically measured offset between the two Öhrstegen 12, 14 is preferably about 40% to 50% of nominal needle size. So that the Öhrstege 12, 14th with their bottom surfaces 16, 17 each approximately on the central axis 4. The rounded eye-side end of the eye bridge 12 goes from its circular arc shape at one point 15 kink and heel-free in a stretched and, as from Figure 1 can be seen, 4 concave with respect to the central axis Floor area 16 over. At the transition area between the Floor surface 16 and the rounded end of the eye web 12 a tangent can be created on the central axis 4 lies or with this a very acute angle of a few degrees.

The same applies to the Öhrsteg 14, also has a concavely rounded bottom surface 17 on the thread running side. A transition point 18 between the floor surface 17 and the rounded end of the eye bridge 14 lies approximately on the central axis 4 and a tangent at this point is correct approximately coincides with the central axis 4. One as flat as possible straight line through the eye 11, which as a tangent to suitable Places the bottom surfaces 16, 17 abuts, closes thus with the central axis 4 an acute angle in the area of a few degrees, preferably less than 20 °.

The eye 11 is relatively narrow. In the axial direction, which is determined by the central axis 4 is the by the axial removal of the ends of the eye webs 12, 14 certain length of the eye preferably about 1 to 1.1 times the nominal needle size of the sewing machine needle 1. This enables good thread guidance. Despite that relatively short eye 11 is due to the offset of the Öhrstege 12, 14 reached an elongated thread. It Embodiments are also possible in which the length of the ear larger or smaller than 1 to 1.1 times that nominal needle size.

Following the eye 11 is along the side 6, a thread groove 21 directed away from the tip 3 formed by two side walls 22, 23 (Figure 3) is limited. These have two essentially flat, mutually parallel flanks on the side 6 are partially touched. The thread groove 21 also has an essentially plan floor 24 that in some Distance runs parallel to the central axis 4. In one approximately the distance from the eye 11 corresponding to the needle size The bottom 24 then begins in the bottom surface 16 of the eye bridge 12 to pass. The floor surface 16 then runs in acute angle to the central axis 4.

The eye 11 is, as can be seen in particular from FIG. 2, delimited by two eye walls 26, 27, the thickness of which measured across the eye 11 (Figure 2, line 28), respectively is slightly less than the clear width of the eye in the area this line 28 passing through the central axis 4. The flanks of the thread groove 21 go with the confluence of the Thread groove 21 in the eye 11 seamlessly in inner surfaces 29, 30 the eye walls 26, 27 over. It can be between the Flanks of the thread groove 21 or the inner surfaces 29, 30 included angles measured transversely to the central axis 4 change along the central axis 4. While the flanks of the Thread groove 21 in the area of cross section III-III (FIG 3) are parallel to each other, the inner walls 29, 30 are in Area of section line II-II (Figure 2) to each other in the acute angle arranged. The inner surfaces 29, 30 diverge however, also to that in the lower one in FIGS. 1 and 2 and upper side of each other, so that the eyelet 11 waisted is. Starting from the eye 11, a short, flat tapering channel 32 towards the tip 3, without this to achieve however. The limited by the bottom surface 17 Channel 32 ends approximately halfway from eye 11 Paths in front of the tip 3. In this area the sewing machine needle points an approximately circular, weakened Cross section on. This cross section is reduced conical in the direction of the tip 3.

On the side of the eye 11 remote from the tip 3 a groove 34 is provided in the shaft 2. This lies opposite the thread groove 21. The fillet 34 has one shown in Figure 3, rounded and rounded back 35 merging into the side surfaces 7, 8. The rounded transitions serve to relieve and protect of the seam material. Also shown is rounded off from FIG. 1 Transition area 36 from the groove 34 to the eye 11. The transition region 36 is formed by the eye bridge 12, being the transition from its rounded end to the outside is formed without edges. From the transition point of the rounded end of Öhrstegs 12 to the Extend the outside or side 5 of the sewing machine needle 1 the eye walls 26, 27 at the same height, without sideways or to protrude upwards in FIG. 1 over the eye bridge 12. While the lower end of the eye 11 in FIG. 1 is the same Height with the entire side 6 of the sewing machine needle 1 lies, the upper end of the eye 11 is arranged somewhat lower than page 5 at least, in the undiminished Shaft area. In other words, the one shown in FIG. height of the parallel to the line 9 to be measured Eye walls 26, 27 is slightly less than the nominal needle size.

The sewing machine needle 1 described so far works as follows:

The sewing machine needle 1 becomes faster when sewing Follow periodically oscillating along its central axis 4 moved back and forth. The sewing machine needle 1 moves first of all at a right angle in front of its tip 3 the central axis 4 arranged sewing material is a through the eye 11 running thread 38 (sewing thread) first stretched passed through the thread groove 21 and the groove 32. The thread 38 is under tension so that it selectively on the bottom surfaces 16, 17 of the earpieces 12, 14 is present. Due to their concave formation, they become flat Plant avoided.

Now the sewing machine needle 1 reverses its direction of movement around and pierces the sewing material, the material shown in FIG illustrated state reached. Tip 3 opens a tap hole in fractions of a millisecond, in that the sewing machine needle 1 up to its eye 11 with expansion of the tap hole. The expansion takes place doing so comparatively gradually, causing the friction between the sewing machine needle 1 and the sewing material even at high Sewing speeds (number of stitches) to a tolerable Dimension is reduced.

The sewing machine needle 1 is with the eye 11 through the Stitched material, the thread 38 around the eye bridge 12 sets. The upper section of the thread 38 in FIG. 4 has only a low relative speed in relation to the sewing material and is more or less in Quiet. The advancing sewing machine needle 1 pulls as in Figure 4 is indicated by arrows in the thread groove 21 lying section of thread 38 at very high speed to. Too much friction between that Thread 38 and the sewing material is due to the considerable depth the thread groove 21 largely minimized. Too much friction at the Öhrsteg 12 is due to its rounding and its minimized considerable thickness, e.g. about with the Diameter of the thread 38 matches.

The sewing machine needle returns as the sewing process continues 1 their direction of movement again, as in Figure 5 is illustrated. The one from the sewing machine needle 1 thread 38 inserted into the sewing material now lifts from it Öhrsteg 12 from. One remains in the eye for now 11 standing loop, which differs from that shown in FIG Sewing machine needle 1 to the left moving eye 14 the eye 11 in the desired direction (Figure 5 vertical is pushed upwards. This is illustrated in Figure 6. A loop 39 is formed by one Gripper 40 can be added for seam formation. The exact formation of this sling is for a working one Sewing process crucial. The Sewing machine needle 1 then passes through again in the return stroke the puncture hole. The thread runs at high speed for wrapping the bobbin case in the opposite direction subtracted from the needle movement. Is the sewing machine needle 1 pulled out of the tap hole and the thread 38 tightened, the process is repeated again.

The sewing machine needle 1 has an axial direction of two eye bridges 12, 14 limited eye 11, which in Axial direction (central axis 4) is relatively short is. Its length is not much greater than the nominal thickness the sewing machine needle 1. eyelets 12, 14 are offset from one another, each eye web 12, 14 is about half as thick as the sewing machine needle 1 in the area of the eye 11. Thus becomes a stable and slim Sewing machine needle 1 created due to their Slenderness puncture holes opens relatively slowly and therefore sews gently even with very high numbers of stitches enables an almost fully protected thread run.

Claims (13)

Sewing machine needle (1), with an essentially straight shaft (2) which adjoins a clamping part, extends along a central axis (4) and ends in a tip (3), with an eye (11) which is delimited by two eye webs (12, 14) spaced apart from one another in the direction of the central axis (4) and offset from one another transversely (9) to the central axis (4). Sewing machine needle according to claim 1, characterized in that the eye webs (12, 14) are rounded are, their radius of curvature preferably with the half the thickness of the eye web (12, 14) matches. Sewing machine needle according to claim 1, characterized in that the eye bridges (12, 14) against each other by one Distance is offset transversely to the central axis (4), the at least 40%, preferably 50% of the nominal needle size is. Sewing machine needle according to claim 1, characterized in that the eye webs (12, 14) each transverse to the Center axis (4) measured have a thickness that is at least 40%, preferably 50% of the nominal needle size. Sewing machine needle according to claim 1, characterized in that the eye bridges (12, 14) with one each Transition area (15, 18) between its front, preferably rounded end and a thread side Bottom surface (16, 17) lie on the central axis (4). Sewing machine needle according to claim 1, characterized in that the eye webs (12, 14) are arranged in such a way and are designed so that an imaginary, through the eye (11) going and on the thread-side bottom surfaces (16, 17) of Eye webs (12, 14) abutting straight line with the central axis (4) includes an acute angle that is less than 20 ° is. Sewing machine needle according to claim 1, characterized in that the eye webs (12, 14) each have a thread side Have bottom surface (16, 17), at least one floor surface, preferably both floor surfaces (16, 17) are concave. Sewing machine needle according to claim 1, characterized in that measured in the direction of the central axis (4) Length of the eye (11) is less than double, nominal needle size. Sewing machine needle according to claim 1, characterized in that measured in the direction of the central axis (4) Length of the eye (11) 1 to 1.1 times the nominal Needle size is. Sewing machine needle according to claim 1, characterized in that each eye bridge (12, 14) with its thread-side Bottom surface of a thread groove (21, 32) is limited. Sewing machine needle according to claim 1, characterized in that the eye walls (26, 27) inner surfaces (29, 30) which are axially spaced apart Include different angles with each other. Sewing machine needle according to claim 1, characterized in that the height of the sewing machine needle (1), measured on the eye (11) perpendicular to the central axis (4) in a direction (9) leading through the eye (11) is than the needle size. Sewing machine needle according to claim 1, characterized in that the eye (11) following the to the Clamping part pointing eye bridge (12) eye walls (26, 27) has that do not protrude laterally beyond the eye bridge (12).

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