Sewing machine needle with recess

Abstract

The present invention provides a sewing machine needle (1) that can be mass-produced economically and reduces friction between a blade (2) of the sewing machine needle (1) and a fabric. The sewing machine needle (1) has a needle eye (3) and at least one recess (5), and the distance between an upper edge (6) of the recess (5) and a lateral position of an axis (12) of the needle eye (3) is different from the distance between a lower edge (7) of the recess (5) and a lateral position of the axis (12) of the needle eye (3).

Description

[Background technology]

[0001] Sewing needles for industrial sewing machines have been known for decades and continue to evolve. In recent years, the use of synthetic fibers in textile products has increased, while sewing speeds have also increased. However, a problem has arisen: synthetic fibers melt at relatively low temperatures during the sewing process. As sewing speeds increase, friction with the needle blade increases the transfer of heat to the fabric. As a result, excessively fast sewing speeds can undesirably melt the synthetic fibers through the needle hole. Despite this problem, attempts have already been made to reduce the friction between the needle blade and the fabric, further increasing sewing speeds.

[0002] EP 2 896 732 A1 describes a sewing needle with a double spiral groove, which includes a groove with two bevels. The bevels reduce the cross section of the needle blade in the groove area, but this does not reduce the friction between the needle blade and the fabric. This is because the bevels are positioned so that they do not come into contact with the fabric during sewing, even in needles without such grooves.

[0003] German Patent No. 962949 describes a sewing needle of this type, which aims to reduce the frictional heat generated during sewing. To this end, the sewing needle has longitudinal grooves extending from the needle eye level to the conical transition between the needle blade and the shank. These grooves are intended to reduce the blade's contact surface with the fabric, thereby reducing friction.

[0004] EP 1 391 548 A1 describes a sewing needle having recesses on two diametrically opposed sides of the needle blade, the recesses being intended to reduce the contact surface between the needle blade and the fabric, thereby reducing friction.

[0005] German Patent Application Publication No. 3149383 describes another example of a sewing needle designed to reduce friction between the needle blade and the fabric. In cross section, the blade has a V-shaped configuration and ribs separated by concave depressions. The shape of the depressions is adjusted to the nature and number of ribs. For example, one embodiment has a star-shaped cross section and seven ribs separated from each other by numerous small depressions. Another embodiment has only four ribs, each separated from each other by a larger depression. The depressions are recesses that penetrate the sewing needle to reduce the cross section of the needle blade. The described "shape" is intended to reduce the contact surface with the fabric and thus reduce friction, but also to increase the surface area of ​​the needle blade, thereby increasing the rate at which generated heat is transferred to the surrounding air.

[0006] Prior art sewing machine needles of this type have proven to be significantly more expensive to manufacture than conventional sewing machine needles and sometimes require additional manufacturing steps. Summary of the Invention

[0007] Therefore, starting from the prior art, it is an object of the present invention to provide a sewing machine needle that reduces friction between the blade of the sewing machine needle and the fabric and does not require additional or more complicated manufacturing steps.

[0008] This object is achieved by a needle for a sewing machine having the following characteristics: a blade extending substantially longitudinally; a needle hole extending through the sewing machine needle in a height direction perpendicular to the longitudinal direction; at least one recess that reduces the reach of the blade in a height direction and a lateral direction perpendicular to the longitudinal direction; At least one recess has an upper edge and a lower edge where the recess (5) ends in the height direction; the recess has, at at least one point along its longitudinal length, a height that is at least 30% of the height of the blade at that point (accordingly, the recess has at least one cross-section in a plane defined by the transverse and height directions, in which the height of the recess is at least 30% of the height of the blade at that cross-section); In addition, the upper edge distance, which corresponds to the lateral distance between the upper edge of the recess and the position in the lateral direction of the axis of the needle eye, is different from the lower edge distance, which corresponds to the lateral distance between the lower edge of the recess and the position in the lateral direction of the axis of the needle eye. The sewing needle preferably has a clamping part (usually a shank) which, in a plane defined by the lateral and height directions, has a larger cross section than the blade and is continued in the longitudinal direction of the needle eye by a transition part. In the plane defined by the lateral and height directions, the cross section of this transition part tapers in the longitudinal direction towards the needle eye. In needles with this type of transition part, the blade adjoins the transition part in the longitudinal direction of the needle eye. The tapering of the transition part can be realized in various ways. Any type of transition part between the blade and the clamping part known to those skilled in the art is conceivable. For example, the transition part may be substantially conical, with a cone axis extending in the longitudinal direction. It is also possible for the surface of the sewing needle to have a step or a radius at the transition part. The formation of recesses in sewing machine needles according to the present invention may be integrated into manufacturing processes already known to those skilled in the art. One or more recesses can be produced simultaneously with the vertical and / or longitudinal movement of the tool, thereby enabling efficient continuous production. The recesses in sewing machine needles can be produced using cutting methods such as milling and / or forming methods such as forging or pressing. Regardless of the number and location of the recesses, it is only necessary to move the tool in the vertical and / or longitudinal directions, as long as the tool is adapted to the shape of the longitudinal recesses. The recesses are formed by processing the needle blank, reducing the cross-sectional area of ​​the needle blank in the plane defined by the lateral and vertical directions in the manner described above. The needle blank before processing may have various cross-sectional shapes, such as circular, oval, trapezoidal, or triangular. Triangular shapes with rounded corners are also contemplated. Other shapes not explicitly mentioned may also be advantageous. A sewing machine needle including at least two recesses is also advantageous, in which case the upper edge distance for each recess is different from the lower edge distance. It is particularly advantageous if the recesses are arranged symmetrically along a plane defined by the axis of the eye and the longitudinal direction of the sewing machine needle.

[0009] Advantageously, the recess has a uniformly shaped portion (uniformly shaped portion) that occupies at least 10%, but preferably at least 20%, of the entire longitudinal reach of the recess, and the height of the recess at any point on this uniformly shaped portion corresponds to at least 30% of the height of the blade at that point. In this way, friction is reduced over a relatively large portion of the sewing machine needle. Note that the uniformly shaped portion does not include the entrance and exit portions of the recess, which are the ends of the recess and face in the longitudinal direction. At the entrance and exit portions of the recess, the upper edges generally approach each other in the height direction until they touch. Advantageously, the height of the recess in the height direction is maximum at at least one point along the length of the uniformly shaped portion. The uniformly shaped portion of the recess is part of the blade, i.e., the blade includes the uniformly shaped portion of the recess.

[0010] Further advantages are obtained if the upper edge distance is smaller than the lower edge distance. A sewing machine needle in which the upper edge distance is smaller than the lower edge distance, at least in the uniform shape of the recess, is particularly advantageous. This type of shape is particularly advantageous when, during at least one manufacturing process, the tool performs a movement with a height direction starting from the upper edge toward the lower edge or a lateral direction component. The upper edge delimits the recess in a positive height direction. The lower edge delimits the recess in a negative height direction. The positive height direction is the direction from the lower edge toward the upper edge. The negative height direction is the direction from the upper edge toward the lower edge, conversely. This definition of the positive height direction and the negative height direction applies to all possible embodiments of the teachings according to the present invention. In a preferred embodiment, the sewing machine needle has at least one scarf and / or at least one thread groove, the scarf being arranged on the upper side facing the positive height direction and the thread groove being preferably arranged on the lower side facing the negative height direction. The thread groove may also be arranged on the upper side facing the positive height direction.

[0011] the needle for the sewing machine includes a groove, the groove being preferably manufactured by a molding process; At least one recess and one gouge may at least partially overlap in the longitudinal direction. In all embodiments, further advantages are obtained. The emery associated with sewing machine needles is already known to those skilled in the art. Any known embodiment of the emery is advantageous. "Overlapping in the longitudinal direction" means that the emery and the recess are at least partially parallel in the longitudinal direction, i.e., they are not separated in the longitudinal direction. It is particularly advantageous if the recess overlaps the emery in the longitudinal direction by at least 10% of the emery length, but preferably by at least 70% of the emery length. The emery length is the length in the longitudinal direction of the needle over which the needle surface at the emery section is recessed in height compared to the surrounding needle sections. The emery length therefore includes the entrance and exit sections of the emery. The blade of a sewing machine needle with an emery can be divided into two subsections: the main cutting section and the emery section. The emery section is the longitudinal section of the emery, including its entrance and exit sections. The main cutting section is the remaining part of the blade. It is advantageous if the uniformly shaped section of the recess mentioned above does not overlap the emery section. The uniformly shaped portion of the recess is advantageously located completely within the main cutting edge, i.e., completely overlaps with it in the longitudinal direction. The main cutting edge advantageously has a uniform cross section in the longitudinal direction (cylindrical cutting edge) or a cross section that tapers slightly in the longitudinal direction (conical cutting edge). The recess of the blade may also be "conical", i.e., its shape may taper in the longitudinal direction towards the pinhole, regardless of the shape of the blade. However, the recess may also be "cylindrical", i.e., maintain the same shape and position in the longitudinal direction, regardless of how the rest of the blade is shaped. In this case, the lateral distance function s(h) of the uniformly shaped portion of the recess is the same at all positions along the length of the uniformly shaped portion. Thus, for example, A cylindrical blade with a cylindrical recess, Cylindrical blade with a conical recess, Conical blade with a cylindrical recess, Conical blade with a conical recess, Many different combinations are possible, such as:

[0012] It is advantageous in all embodiments of the sewing needle if, at least at one point along the longitudinal length of the recess, but preferably at all points along the length of the uniformly shaped portion, the maximum height distance between the upper edge of the recess and the highest point of the blade is 35% of the height of the blade, but preferably 25% of the height of the blade, which results in a large recess and effectively reduces the friction surface between the sewing needle and the fabric.

[0013] It is advantageous if the lateral distance function s(h), which describes the lateral distance between the surface of the sewing needle and the axis of the needle eye in dependence on the height coordinate, decreases monotonically, preferably strictly monotonically, with increasing height over at least 90% of the height reach of the recess, but preferably over the entire height reach of the recess. The height reach of the recess is the extension of the recess in the height direction. In this way, undercuts are avoided and the manufacturing process is further facilitated. The lateral distance function s(h) is also a function of the cross-sectional curve of the surface of the sewing needle in the plane defined by the height and lateral directions, and describes the lateral distance between the surface of the sewing needle and the axis of the needle eye in the lateral direction in dependence on the height coordinate h. The height coordinate h increases in the positive height direction H. The first derivative of the lateral distance function s'(h) decreases monotonically, preferably strictly monotonically, with increasing height over the height coordinate h of the upper edge. O and the height coordinate of the lower edge h U Negative for height coordinates greater than (i.e., h U <h<h O In this case, it is advantageous if s'(h)<0). The second derivative of the horizontal distance function s''(h) is the height coordinate of the lower edge h U and the height coordinate of the upper edge h O is less than or equal to zero for height coordinates greater than (i.e., h>h O or h <h U In this case, it is particularly advantageous if s″(h)≦0).

[0014] It is even more advantageous if at least one recess is laterally spaced apart from the position of the axis of the needle hole at all points. Advantageously, the lateral distance between the recess and the position of the axis of the needle hole is greater than zero at all points of the recess. In this way, the plane defined by the axis of the needle hole and the longitudinal direction does not intersect with the recess. Needles having at least two such recesses symmetrical with respect to the plane defined by the axis of the needle hole and the longitudinal direction are particularly advantageous.

[0015] An advantageous embodiment is obtained if the lead-in tangent of the recess at its upper edge makes an angle of 5° to 70°, but preferably 10° to 40°, with respect to the height direction. The lead-in tangent is a tangent that is adjacent to the surface of the recess in the plane defined by the transverse and height directions. The lead-in tangent is tangent to the upper edge. In the region of the upper edge, the recess may be variously rounded depending on the manufacturing method. Such rounding results in a large change in the slope of the surface in the plane defined by the height and transverse directions, so that the lead-in tangent is not tangent. In a preferred embodiment, the lead-in tangent contacts the recess at the concave part of its surface. It is particularly advantageous if the imaginary tangent in the plane defined by the transverse and height directions makes an angle of at least 5°, but preferably at least 10°, at all points on the surface of the recess.

[0016] A sewing machine needle may advantageously include at least one thread groove extending substantially longitudinally, continuing from the eye of the needle in the negative longitudinal direction (i.e., as viewed from the eye of the needle toward the blade), and forming a recess in the height direction. In a preferred embodiment, the thread groove is located on the lower side of the needle facing the negative height direction. In this case, the thread groove is "open" in the negative height direction, i.e., it is not bounded in the negative height direction by the material of the sewing machine needle. However, the thread groove may also be located on the upper side facing the positive height direction. In this case, the thread groove is "open" in the positive height direction. The thread groove is suitable for receiving the thread passing through the eye of the needle and guiding it longitudinally along the blade. A thread groove that ends at the eye of the needle has advantages. In this case, the thread groove and the eye of the needle merge with each other in the longitudinal direction, i.e., no needle material is located between the needle eye and the thread groove. However, the thread groove can also be spaced apart from the eye of the needle. The thread groove is a slot-shaped recess in the needle blade. The thread channel is separated on one side in the height direction and on both sides in the lateral direction by the material of the needle. Advantageously, the sewing machine needle includes two thread channels. Particularly advantageous are sewing machine needles having a first thread channel on the lower side and a second thread channel on the upper side.

[0017] It is advantageous if, at least at one point along the longitudinal length of the recess, but preferably at all points along the length of the uniformly shaped portion, in the region between the lower and upper edges, the surface of the needle is formed as an arc of a substantially constant radius in the plane defined by the height and lateral directions, the center of this arc preferably being located outside the cross-sectional area of ​​the needle in the plane defined by the height and lateral directions. Accordingly, in this cross-section, the surface of the recess has the shape of an arc, the radius of which is the same at all points on this arc. Such a recess shape can be easily produced by both cutting and molding. A further advantage is obtained if, in the plane defined by the height and lateral directions, the surface of the needle between the lower and upper edges of the recess has a shape consisting of an arc and a straight line adjacent to this arc. This straight line is preferably adjacent to the tangent of the arc.

[0018] A further advantage is provided by a sewing needle in which, at at least one point along the longitudinal length of the recess, but preferably at all points along the length of the uniformly shaped portion, the recess height (recess height), corresponding to the heightwise distance between the upper and lower edges, is 60% to 170% of the maximum value of the lateral distance function s(h), but preferably 75% to 160% of the maximum value of the lateral distance function s(h). The above-mentioned selection range has been found to be advantageous for sewing needles having conventional dimensions, since it allows for the use of simple manufacturing methods and at the same time promotes the sewing needle to generate little friction with the fabric during sewing. Advantages are also obtained with a sewing needle in which, at at least one point along the length of the recess, but preferably at least 20% of the length of the recess, the recess height, corresponding to the heightwise distance between the upper and lower edges, is 25% to 150% of the maximum value of the lateral distance function s(h), but preferably 35% to 105% of the maximum value of the lateral distance function s(h). Particularly advantageous is a needle for a sewing machine in which, for at least 20% of the gouge length, the recess height, which corresponds to the height distance between the upper edge and the lower edge, is 35% to 60% of the maximum value of the lateral distance function s(h).

[0019] A further advantage is obtained by a sewing machine needle when it holds that at at least one point along the longitudinal length of the recess, but preferably at all points along the length of the uniformly shaped portion, the upper edge distance O is 10% to 60% of the maximum value of the lateral distance function s(h), but preferably 25% to 45% of the maximum value of the lateral distance function s(h). The upper edge distance O is the height of the upper edge h O In other words, O=s(h O). The above-mentioned selection range has proven advantageous for sewing machine needles with conventional dimensions, since it allows for the largest possible size of the recess and therefore the greatest possible reduction in friction, yet is easy to manufacture and ensures sufficient stability of the sewing machine needle. Particularly advantageous are sewing machine needles in which, at at least one point along the gore length, but preferably over at least 20% of the gore length, the upper edge distance O is between 10% and 75% of the maximum value of the lateral distance function s(h), but preferably between 35% and 65% of the maximum value of the lateral distance function s(h).

[0020] A further advantage is obtained by a sewing machine needle when it holds that at at least one point along the longitudinal length of the recess, but preferably at all points along the length of the uniformly shaped portion, the lower edge distance U is 50% to 100% of the maximum value of the lateral distance function s(h), but preferably 70% to 95% of the maximum value of the lateral distance function s(h). U In other words, U=s(h U ). The above-mentioned selection range has been found to be advantageous for sewing needles with conventional dimensions, since it allows for the largest possible recess size and therefore the greatest possible reduction in friction, yet is easy to manufacture and ensures sufficient stability of the sewing needle. Advantages are obtained with a sewing needle in which, at all points along the gore length, the lower edge distance U is between 50% and 100% of the maximum value of the lateral distance function s(h), but preferably between 70% and 95% of the maximum value of the lateral distance function s(h)h).

[0021] A method of manufacturing a sewing machine needle, the sewing machine needle having a blade extending substantially in a longitudinal direction and a needle hole extending through the sewing machine needle in a height direction perpendicular to the longitudinal direction, comprising: At least one recess bounded by an upper edge and a lower edge in the height direction, an upper edge distance corresponding to the lateral distance between the upper edge of the recess and the lateral position of the axis of the pinhole; different from the lower edge distance corresponding to the distance in the lateral direction between the lower edge of the recess and the position in the lateral direction of the axis of the pinhole, The object of the present invention is achieved by manufacturing the product by only moving the tool in the height direction and / or the longitudinal direction. The tool movement in two directions, or limited to one direction, allows for a particularly efficient production process. This type of method allows for the continuous production of large quantities of sewing machine needles. This type of method is particularly advantageous for sewing machine needles in which the recess has a height, at at least one point along its longitudinal length, that corresponds to at least 30% of the height of the blade at that point.

[0022] A further advantage is achieved by the method in which at least one recess is produced by a separate process, preferably by milling. If the contour of the milling cutter corresponds to the contour of the recess, the recess can be produced with horizontal and longitudinal movements. No additional lateral movements are required. This method can also be advantageously used with other separate-type manufacturing methods, such as grinding or electrical discharge machining.

[0023] Further advantages are obtained by the method in which at least one recess is produced by a molding process, preferably by pressing. When the press comprises an upper and lower die that mirror the contours of at least one recess or multiple recesses, the recesses can be produced solely by moving the tool in the vertical direction. This is a particularly simple and efficient method for producing recesses in sewing machine needles. However, the recesses can also be produced by molding in a press with more than two dies, for example, a press with three, four, or five dies. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 shows a needle (1) for a sewing machine having a recess (5). [Figure 2] FIG. 2 shows the same sewing machine needle (1) as in FIG. 1 rotated 180 degrees around the needle axis. [Figure 3] FIG. 3 is a side view of a sewing machine needle (1) having a recess (5). [Figure 4] FIG. 4 is a diagram showing a cross section AA of the needle for sewing machine (1) of FIG. 3, which is pierced by a plane defined by the lateral direction (B) and the longitudinal direction (H). [Figure 5] FIG. 5 shows the same cross section as FIG. 4 and the transition of the lateral distance function s(h). [Figure 6] FIG. 6 is a view showing a cross section BB passing through the needle for sewing machine (1) of FIGS. 3 and 4 in a plane defined by the height direction (H) and the longitudinal direction (L). [Figure 7] FIG. 7 is a diagram showing a cross section passing through the needle (1) for a sewing machine at the position of the needle eye (3). [Figure 8] FIG. 8 shows various needle blanks (8) and the cross-sectional reduction caused by recesses (5) and thread channels (4). [Figure 9] FIG. 9 is a diagram showing a cross section passing through a needle (1) for a sewing machine and a fabric (29) having a thread eye (28). [Figure 10a] FIG. 10a shows a first variant of the progression of the lateral distance function s(h) in the region of the recess (5). [Figure 10b] FIG. 10b shows a second variant of the progression of the lateral distance function s(h) in the region of the recess (5). [Figure 10c] FIG. 10c shows a third variant of the progression of the lateral distance function s(h) in the region of the recess (5). [Figure 10d] FIG. 10d shows a fourth variant of the progression of the lateral distance function s(h) in the region of the recess (5). DETAILED DESCRIPTION OF THE INVENTION

[0025] FIG. 1 shows a three-dimensional view of a sewing needle 1 with a recess 5 (the second recess 5 is obscured in this view). The sewing needle 1 comprises a clamping section 18, a transition section 19, a cutting section 23, a main cutting section 22, a uniform section 37, an indentation 16, and an eye 3. The axis 12 of the eye 3 extends in the height direction H and is located in the transverse direction B, centrally between the two side walls 9 of the eye 3. In this embodiment, the uniform section 37 corresponds to the main cutting section 22, i.e., these two sections completely overlap. In other embodiments of the teachings according to the invention, it may be advantageous for the main cutting section 22 and the uniform section 37 to only partially overlap. In this example, the uniform section does not overlap the indentation 24.

[0026] 2 shows the sewing machine needle of FIG. 1 rotated 180° about the longitudinal axis 17. On the underside of the sewing machine needle 1, the thread groove 4 faces in the negative height direction H and extends in the longitudinal direction L from the needle eye 3 to the transition portion 19. Therefore, in the longitudinal direction L, the thread guide 4 overlaps with the cutting edge 23 and the transition portion 19.

[0027] FIG. 3 is a side view of a sewing machine needle 1 having a clamping portion 18, a blade portion 23, and a tapered portion 20. It is advantageous for all needle embodiments if the clamping portion 18 includes a shank 25. In all embodiments, the clamping portion 18 is adapted to be received in a sewing machine and driven longitudinally to produce a sewing action. The blade portion 23 is the portion within which the blade 2 extends longitudinally. The blade portion 23 includes a main blade portion 22 and a gouge portion 24. When viewed in the longitudinal direction L toward the needle eye 3, the main blade portion 22 is located in front of the gouge portion 24. The gouge portion 24 is the portion within which the gouge 16 extends in the longitudinal direction L. In the main blade portion 22, the blade 2 has a uniform cross section along the longitudinal direction L. Those skilled in the art would describe such a blade as cylindrical. It may also be equally advantageous for all embodiments of the invention if the cross section of the blade 2 decreases in the longitudinal direction L at the main blade portion 22 toward the needle eye 3. Those skilled in the art would describe such a blade as conical. The blade portion 23 has a smaller cross section than the clamping portion 18. A conical transition 19 between the clamping portion 18 and the blade portion 23 or main cutting portion 22 equalizes this difference in cross section between the clamping portion 18 and the blade portion 23. When viewed in the longitudinal direction L away from the clamping portion 18, a tapered portion 20 adjoins the blade portion 23. At this point, the cross section of the needle decreases monotonically and terminates at the needle tip 21. A recess 5 is arranged in the blade portion 23, the cross section of which in the longitudinal direction L also overlaps with the transition portion 19. The recess includes a uniformly shaped portion 37 that completely overlaps the main cutting portion 22. The uniformly shaped portion 37 is bounded in the longitudinal direction L at the same position as the main cutting portion 22. However, in other embodiments of the present teachings, the boundary defining the uniformly shaped portion 37 may deviate from the boundary defining the main cutting portion 22. The recess 5 is bounded in the height direction by an upper edge 6 and a lower edge 7. It is also advantageous in all embodiments if the recess 5 is located completely within the cutting portion 23, i.e., both the beginning and the end of the recess 5 in the longitudinal direction L are located within the cutting portion 23. In the longitudinal direction, the recess 5 overlaps the gouge 16 by an overlap length 26. Thus, part of the recess is also located within the gouge portion 24. In this example, the overlap length 26 corresponds to 90% of the gouge length 27 in the longitudinal direction L.However, it is advantageous in all embodiments if the overlap length 26 is at least 10%, preferably at least 70%, of the gouge length 27. It can be equally advantageous for the sewing machine needle 1 according to the invention if the recess 5 does not overlap the gouge 16 in the longitudinal direction L.

[0028] FIG. 4 shows a cross section AA through the needle 1 for sewing machines in the position shown in FIG. 3 . This cross section is located at the end of the blade portion 23, just before the transition section 19 begins in the longitudinal direction L. Therefore, this figure shows the cross section of the blade 2 farthest from the needle eye 3 in the longitudinal direction L. The blade 2 has two recesses 5 and a thread groove 4. The recesses 5 reduce the cross section of the blade 2 and have a concave shape in the plane of the cross section. Behind the plane of the cross section, the shank 25, which has a larger cross section than the blade 2, is visible. The upper edge 6 and the lower edge 7 are cut by the plane of the cross section and divide the recesses 5 into upper and lower parts in the height direction H. FIG. 4 also shows the lateral position of the axis 12 of the needle eye 3. Each upper edge 6 is spaced from the axis 12 of the needle eye 3 by an upper edge distance O in the transverse direction B, and each lower edge 7 is spaced from the axis 12 of the needle eye 3 by a lower edge distance U in the transverse direction B. The upper edge distance O and the lower edge distance U are different in size, with the upper edge distance O being smaller than the lower edge distance U. In all embodiments of the present invention, the recess height 11, which corresponds to the distance between the upper edge 6 and the lower edge 7 in the height direction H, is greater than 30% of the shank height 10 of the blade 2 in the height direction H. The surface 13 of the needle 1 is laterally spaced a lateral distance s from the position of the axis 12 of the needle eye 3. The lateral distance s can be described by a lateral distance function s(h) that depends on the height coordinate h in the height direction (i.e., s = f(h) = s(h)). A lead-in tangent 14, which is tangent to the curve of the lateral distance function s(h) at the upper edge 6 of the recess 5, forms a lead-in angle 15 with the height direction H that is greater than 5° in its end region. However, the selection range of the lead-in angle 15 described in the previous paragraph is advantageous in all embodiments of the needle 1.

[0029] Figure 5 shows the same cross section as Figure 4, again showing the lateral distance function s(h). The upper edge distance O is calculated by multiplying the height coordinate h of the upper edge 6 by OThe value of the lateral distance function s(h) at O The lower edge distance U corresponds to the height coordinate h of the lower edge 7. U The value of the lateral distance function s(h) at U In this embodiment, the lateral distance s decreases strictly monotonically within the height reach of the recess 5 as the height coordinate increases in the height direction. Therefore, over the entire recess height 11, the derivative of the lateral distance function s(h) is less than zero (h O >h>h U s'(h)<0). This type of curve progression can be advantageous in all embodiments. Similarly, it is desirable for the lateral distance to decrease monotonically with increasing height, i.e., for the derivative of the lateral distance function s(h) to be less than or equal to zero (h O >h>h U In all variants, it is also advantageous if s'(h)≦0. U The smaller height coordinate and the height coordinate h of the upper edge 6 O Second derivative of the lateral distance function for larger height coordinates s''(h) is less than 0 (h>h O or h <h U If , then s''(h)<0).

[0030] FIG. 6 shows a cross section B-B through the needle 1 in a plane defined by the axis 12 of the needle eye 3 and the longitudinal direction L. The needle eye 3 is located in the tapered portion 20 of the needle 1. The axis 12 of the needle eye 3 is located at the center of the needle eye 3 in the longitudinal direction. At the rear of the cross section, as viewed in the drawing, the needle eye 3 is bounded in the transverse direction B by a side wall 9. A thread groove 4 is formed adjacent to the needle eye 3 on the underside of the needle 1. The needle eye 3 and the thread groove 4 are not separated from each other in the longitudinal direction L but merge into each other. The thread groove 4 extends over the entire blade portion 23 and terminates within the transition portion 19. The thread groove 4 is a recess in the blade 2 of the needle 1 suitable for receiving a sewing thread during the sewing process. A wide variety of thread grooves 4 have been known to those skilled in the art for many years. The teachings of the present invention can be advantageously combined with thread grooves 4 of all shapes and forms.

[0031] Figure 7 shows a cross section CC through the same sewing machine needle 1 as in Figure 6, at the position of the needle eye 3 in the plane defined by the height direction H and the lateral direction B. The needle eye 3 is bounded on both sides by side walls 9 in the lateral direction B. In the lateral direction B, the axis 12 of the needle eye 3 passes through the exact center of the needle eye 3. The axis 12 of the needle eye 3 has this position in the lateral direction B as in all other embodiments of the present invention. Also shown on the underside of the sewing machine needle 1 is the thread channel 4 immediately adjacent to the needle eye 3.

[0032] FIG. 8 shows possible shapes of needle blank 8 and possible arrangements of recesses 5 for each shape. The cross section of needle blank 8 may be circular 32, elliptical 33, trapezoid 34, triangular 30, or triangular 31 with rounded corners. However, the needle blank may also have a cross-sectional shape 35 consisting of two arcs of different radii and two diagonally oriented straight lines connecting the arcs. How recesses 5 according to the present invention reduce the cross section of needle blank 8 having these shapes is clear from the second column of FIG. 8. The third column of FIG. 8 shows how thread grooves 4 reduce the cross section of needle blank 8 having these shapes. The teachings of the present invention can also be used advantageously with needle blanks 8 having all other known cross-sectional shapes for sewing machine needles 1.

[0033] FIG. 9 shows a cross section through the needle 1 and the fabric 29 at the position of the eye 28 (a hole made in the fabric by the needle). The fabric 29 is not in contact with the needle 1 in the region of the recess 5. Therefore, there can be no friction in this region, resulting in a reduction in overall friction between the needle 1 and the fabric 29. In FIG. 9, the eye 28 is shown as an idealized circle. Depending on the fiber and mechanical properties of the fabric 29 and the cross-sectional shape of the needle, other shapes for the eye 28 may be obtained. However, all of these have in common that the fabric 29 and the needle 1 are not in contact with each other in the region of the recess 5.

[0034] 10a to 10d show four alternative cross-sectional shapes of the recess 5 of the sewing machine needle 1 and the corresponding progression of the lateral distance function s(h). These alternative cross-sectional shapes can be advantageously combined with all possible embodiments of the present invention. In the embodiment of FIG. 10a, the lateral distance function s(h) between the upper edge 6 and the lower edge 7 of the recess 5 is composed of two straight lines with different slopes (neither of which is equal to zero). In the embodiment of FIG. 10b, the lateral distance function s(h) between the upper edge 6 and the lower edge 7 of the recess 5 is composed of five straight lines. The consecutive straight lines have different slopes, and none of these slopes is equal to zero. In the embodiment of FIG. 10c, the lateral distance function s(h) between the upper edge 6 and the lower edge 7 of the recess 5 is composed of three circular arcs. FIG. 10d shows an embodiment with a lateral distance function s(h) composed of a circular arc and a straight line adjacent to this circular arc in the positive height direction H. The figure shows a transition point 36 between the straight lines and the circular arcs. The arc begins at the lower edge 7 in the positive height direction H and terminates at a transition point 36. A straight line is tangent to the arc at the transition point 36 and continues in the positive height direction H, terminating at the upper edge 6. [Explanation of symbols]

[0035] 1: Needle for sewing machine 2: Blade 3: Needle hole 4: Thread groove 5: Recess 6: Upper edge of recess (5) 7: Lower edge of recess (5) 8: Needle blank material 9: Side wall of pinhole (3) 10: Blade height 11: Recess (5) height 12: Shaft of pinhole (3) 13: Surface of sewing machine needle (1) 14: Introduction tangent 15: Introduction angle 16: Eguri 17: Longitudinal axis 18: Clamp section 19: Transition section 20: Tapered section 21: Needle tip 22: Main blade part 23: Blade part 24: Eguri Club 25: Shank 26: Overlap length 27: Eguri (16) Length 28: Thread hole 29: Fabric 30: Needle blank material having a triangular cross section (8) 31: Needle blank material having a triangular cross section with rounded corners (8) 32: Needle blank material having a circular cross section (8) 33: Needle blank material having an oval cross section (8) 34: Needle blank material having a trapezoidal cross section (8) 35: Needle blank material having a cross-sectional shape consisting of two arcs and two straight lines (8) 36:Transition point 37: Uniform shape portion of recess (5) B: Horizontal L: Longitudinal direction H: Height h: height coordinate s: lateral distance s(h): Horizontal distance function depending on height coordinate (h) O: Upper edge distance U: Lower edge distance h O : Height coordinate at the height of the upper edge (6) h U : Height coordinate at the height of the lower edge (7)

Claims

1. a blade (2) extending substantially in a longitudinal direction (L); A needle hole (3) extending through the sewing machine needle (1) in a height direction (H) perpendicular to the longitudinal direction (L); a gouge portion (24) of the blade (2) extending in the longitudinal direction (L) and including a gouge (16); at least one recess (5) formed in the blade (2) and configured to reduce friction between the blade (2) and the fabric, the at least one recess (5) extending outside the gouge portion (24) in the longitudinal direction (L) and shortening the reach of the blade (2) in a height direction (H) and a transverse direction (B) perpendicular to the longitudinal direction (L); At least one of the recesses (5) has an upper edge (6) and a lower edge (7) where the recess (5) ends in a height direction (H), the recess (5) has, at at least one point along its length in the longitudinal direction (L), a height (11) that corresponds to at least 30% of the height (10) of the blade (2) at that point; An upper edge distance (O) corresponding to the distance in the lateral direction (B) between the upper edge (6) of the recess (5) and the position of the axis (12) of the pinhole (3) in the lateral direction (B) is: The needle (1) for a sewing machine is characterized in that the lower edge distance (U) is different from the lower edge distance (U) corresponding to the distance in the lateral direction (B) between the lower edge (7) of the recess (5) and the position in the lateral direction (B) of the axis (12) of the needle hole (3).

2. 2. The needle (1) for a sewing machine according to claim 1, characterized in that the recess (5) has a uniformly shaped portion (37) occupying at least 10% of the total reach of the recess (5) in the longitudinal direction (L), and the recess (5) has a height (11) at every point on the uniformly shaped portion (37) that corresponds to at least 30% of the height (10) of the blade (2) at that point.

3. 3. The needle (1) for a sewing machine according to claim 1 or 2, wherein the upper edge distance (O) is smaller than the lower edge distance (U).

4. A needle (1) for a sewing machine as described in any one of claims 1 to 3, characterized in that at least one of the recesses (5) and the grooves (16) at least partially overlap in the longitudinal direction (L).

5. At least one point along the length of the recess (5) in the longitudinal direction (L), The distance in the height direction (H) between the upper edge (6) and the highest point in the height direction of the blade (2) is 5. The needle (1) for sewing machines according to any one of claims 1 to 4, characterized in that it is at most 35% of the height of the cutting edge (10).

6. 6. The sewing machine needle (1) according to any one of claims 1 to 5, characterized in that a lateral distance function (s(h)) describing the lateral (B) distance between the surface (13) of the sewing machine needle (1) and the axis (12) of the needle eye (3) as a function of the height coordinate (h) monotonically decreases with increasing height over at least 90% of the height reach of the recess (5).

7. 7. The needle (1) for a sewing machine according to any one of claims 1 to 6, characterized in that at least one recess (5) is spaced at all points in the lateral direction (B) from the position of the axis (12) of the needle eye (3).

8. 8. The needle (1) for a sewing machine according to claim 1, wherein a lead-in tangent (14) of the recess (5) at the upper edge (6) forms a lead-in angle (15) of 5° to 70° with respect to a height direction (H).

9. 9. The needle (1) for a sewing machine according to claim 1, characterized in that at least one thread groove (4) extending substantially in the longitudinal direction (L) continues from the needle eye (3) in the negative longitudinal direction (L) and forms a recess in the height direction (H).

10. At least one point along the length of the recess (5) in the longitudinal direction (L), In the region between the lower edge (7) and the upper edge (6), in a plane defined by the height (H) direction and the lateral direction (B), the surface (13) of the needle (1) for sewing machines is formed as an arc having a substantially constant radius; 10. The needle (1) according to any one of claims 1 to 9, wherein the center of the arc is located outside the area of ​​the cross section of the needle (1) in a plane defined by the height direction (H) and the lateral direction (B).

11. At least one point along the length of the recess (5) in the longitudinal direction (L), 11. The needle (1) for a sewing machine according to any one of claims 1 to 10, characterized in that a height (11) of the recess, which corresponds to a distance in a height direction (H) between the upper edge (6) and the lower edge (7), is between 60% and 170% of a maximum value of a lateral distance function (s(h)).

12. At least one point along the length of the recess (5) in the longitudinal direction (L), 12. The needle (1) for a sewing machine according to any one of claims 1 to 11, characterized in that the upper edge distance (O) is between 10% and 60% of the maximum value of the lateral distance function (s(h)).

13. At least one point along the length of the recess (5) in the longitudinal direction (L), 13. The needle (1) for a sewing machine according to any one of claims 1 to 12, characterized in that the lower edge distance (U) is between 50% and 100% of the maximum value of the lateral distance function (s(h)).

14. A method for manufacturing a sewing machine needle (1), the sewing machine needle comprising: a blade (2) extending substantially in a longitudinal direction (L); A needle hole (3) extending through the sewing machine needle (1) in a height direction (H) perpendicular to the longitudinal direction (L); a gouge portion (24) of the blade (2) extending in the longitudinal direction (L) and including a gouge (16); at least one recess (5) formed in the blade (2) and configured to reduce friction between the blade (2) and the fabric, the at least one recess (5) extending outside the gouge portion (24) in a longitudinal direction (L) and delimited by an upper edge (6) and a lower edge (7) in a height direction (H); An upper edge distance (O) corresponding to the distance in the lateral direction (B) between the upper edge (6) of the recess (5) and the position of the axis (12) of the pinhole (3) in the lateral direction (B) is so as to be different from a lower edge distance (U) corresponding to the distance in the lateral direction (B) between the lower edge (7) of the recess (5) and the position of the axis (12) of the pinhole (3) in the lateral direction (B), A method for manufacturing a needle (1) for a sewing machine, characterized in that the needle is manufactured by moving a tool only in the height direction (H) and / or the length direction (L).

15. 15. The method for manufacturing a needle (1) for a sewing machine according to claim 14, characterized in that the at least one recess (5) is manufactured by a separation process or by a molding process.

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