Title of Invention

"SEWING-MACHINE NEEDLE"

Abstract

A sewing-machine needle (1) with a shank (3) which extends from a butt (2) and on its lateral surface - extending from the eye (8) at the needle - point end -has at least one thread groove (11) which runs in the direction of the butt (2) and the groove base (12) of which is configured as a curved surface (W) located in the transverse direction of the shank (3) , the side flanks (15) which belong to the thread groove, and extend from the end point of the curved region, forming a groove cross-section (16) which widens in the direction of the lateral surface (4), characterized in that the diameter (D) of the circle-arc - shaped curved contour of the curved surface (W) is equal to the radius (R) of the shank (3).

Full Text

ORIGINAL IN/PCT/02; 105/MUM FORM 2 THE PATENTS ACT 1970 [39 OF 1970] THE PATENTS RULES, 2003 COMPLETE SPECIFICATION [See Section 10; rule 13] "SEWING-MACHINE NEEDLE" RHEIN-NADEL MASCHINENNADEL GMBH, of Reichsweg 19-42, D-52068 Aachen, Germany The following specification particularly describes the invention and the manner in which it is to be performed: 12-5-2006 GRANTED 22 MAR 2006 Sewing-machine needle The invention relates to a sewing-machine needle with a shank which extends from a butt and on its lateral surface - extending from the eye at the needle-point end - has at least one thread groove which runs in the direction of the butt and the groove base of which is configured as a curved surface located in the transverse direction of the shank, the side flanks which belong to the thread groove, and extend from the end point of the curved region, forming a groove cross-section which widens in the direction of the lateral surface. A sewing-machine needle with a classically round shank cross-section is known from DE 31 49 383 Ai (Figure 4). The thread groove is of rectangular contour; the parallel side flanks are connected via a groove base which is oriented at right angles to them, likewise as a flat flank. German Patent Specification 193 006 discloses a trapezoidal thread-groove contour. The side flanks diverge in the direction of the lateral surface. This results in a considerably widened groove cross-section. The groove base has a predominantly planar surface and merges into the wall sections of the side flanks via a short concave rounded portion in each case. Along with a shank cross-section which is also round in this case, this sewing-machine needle is provided, diametrically opposite the thread groove, with a supplementary groove of relatively flat configuration (Figure 3). DE 32 35 153 Al discloses a sewing-machine needle of the generic type, the groove base of which is configured as a curved surface which is located in the transverse direction of the shank and adjoins diverging side flanks, which side flanks form a groove cross- section which widens in the direction of. the lateral surface (Figure 11a) The groove base, more like a notch valley, is of relatively narrow formation. With the knowledge of these given features, it has been an object of the invention to form a sewing-machine needle of the type described which, while having a groove contour which is advantageous for thread guidance is more resistant to bending forces. This object is achieved first and foremost in the case of a sewing-machine needle having the features of Claim 1, this being based on the fact that the diameter of the circle-arc-shaped curved contour of the curved surface corresponds approximately to the radius of the shank. The resulting groove base is not narrow, thus reduces frictional heat and, in the process, nevertheless leaves behind it sufficient cross-section for the shank not to be weakened. The curved contour is at such a depth that it is possible to configure the zone some way after the shank-periphery semicircle for the sought-after enlarged groove cross-section. Even the fracture-critical transition regions have lost some of their notch effect. The corners are "ironed out". The generous concave rounding produces advantageously located blocking surfaces in relation to bending forces, both in the direction of the needle eye and transverse thereto. A considerable stiffening effect is achieved. It is advantageous here for the curved contour of the curved surface to be configured such that two tangents which are applied to the curved contour from a point (vertex) located, in the shank cross-section, on the far side of the shank center and on the longitudinal center plane of the shank (tangent-application point) define a widening clearance cross-section and an interstice section which is smaller, or at most, has the same surface area, is located above the tangent-application point and is formed, on the one hand, by the curved line of the curved surface and on the other hand, by the tangent applied in the curvature vertex and the radial line located at right angles thereto and the straight line running through the tangent point, located parallel to the longitudinal center plane running through the center of the shank and the center point of curvature. The material removed Sox widening purposes has something of a corner-filling function and is thus added to the rounded part of the groove base in order to alleviate the problem of notch fracturing. This forms the generously concavely rounded extremities of the widened groove cross-section. The cross-sectional relationships, in respect of the difference in size of the surface areas of the widening-clearance cross-section and the interstice section, are, at most, somewhat less than 30%. Furthermore, an advantageous solution is achieved by a supplementary groove which is located opposite the thread groove in a manner known per se, is of smaller cross-section and has a curved base surface and a mouth width approximately of the clear mouth width of the thread groove, the side flanks of the latter running into the lateral surface of the shank at an obtuse angle. Such a supplementary groove is of lesser depth than the customary long thread groove. The concave rounding contour helps to achieve a polydirectional wall alignment of the shank and thus an increase in the resistance in relation to bending forces. Such sewing-machine needles or also so-called double-groove needles have virtually a double-T profile, the groove-forming transitions, in the manner described, not being at risk as far as a riotch effect is concerned. It is advantageous here, in the case of two mutually opposite thread grooves with the same geometry, corresponding to the characterizing clause of the second claim, for the vertices of the applied tangents to meet, or even overlap, in the region of the longitudinal center axis of the shank, that is to say in the region of the center. The subject matter of the invention is explained in more detail hereinbelow with reference to an exemplary embodiment illustrated in the drawing, in which: Figure 1 shows, on an enlarged scale, a view of a sewing-machine needle realized as a double-groove needle, to be precise as seen in the direction of a thread groove, Figure 2 shows the section along line II-II in Figure 1, Figure 3 shows the bottom view of the sewing-machine needle, to be precise, as seen in the direction of the hollow channel, Figure 4 shows a vastly enlarged cross-section through the shank of the sewing-machine needle, having a supplementary groove, Figure 5 shows a corresponding cross-section showing the sewing-machine needle as a double-groove needle, and Figure 6 shows the same thing with modified geometry (the sectional hatching has been omitted from these two illustrations). The sewing-machine needle 1, which may be produced as a blank by cold stretching in the classic reducing process using a rotary press, by metal-cutting, or even by way of compression molding/clipping such that, as far as possible, no follow-up processing is required, is basically of circular cross-section. This applies to the cross-sectionally larger butt 2 and to the shank 3 of the sewing-machine needle 1, this shank taking up the largest length section. As far as the shank cross-section is concerned, you are referred to Figures. 4 to 6. There, the cylindrical lateral surface of the same is designated 4. The butt 2 merges, via a frustoconical extension 5, into the markedly cross-sectionally reduced shank 3, which terminates with a needle point 6. The needle point 6 extends in the eye end section 1' of the sewing-machine needle 1. The actual tip is 7. The eye is designated 8. The so-called hollow channel 9 is located in front of the eye. The hollow channel forms an enlarged space for the feed dog (not illustrated) of a sewing-machine. A thread groove 11 runs in the rear of the hollow channel 9, that is to say on the side directed away from a protuberance 10. The groove base is designated 12. The thread groove 11 runs continuously, and substantially at the same depth, between the eye 8 in the end section 1' and the extension 5. It is only the extension end region which tapers as it passes on to the lateral surface of the truncated cone of the extension 5. The butt 2 itself is uniformly cylindrical. It would also be possible, however, for it to be slightly conical or stepped. Its free end section is designated 1' . This butt end section is beveled. At a diametrically opposite location, in relation to the cross-section of the shank 3, on the side directed away from the thread groove 11, the shank 3 has another thread groove 13. This is of lesser radial depth than the thread groove 11 and is configured as can be seen from Figure 5 or as can be gathered from Figure 4, in which case it is realized as a supplementary groove 14. The further thread groove 13 is closed at its ends spatially in front of the eye 8, at this location, or on the one hand, by the abovementioned protuberance 10 and, on the other hand, by the lateral surface of the extension 5, this lateral surface sloping up in relation to the groove depth. The tapering mentioned in respect of the groove 11 also takes place here. The longitudinal extent of the grooves 11, 13, 14 correspond to one another, to be precise in a space-parallel manner in relation to the center Z of the shank 3, the center forming a longitudinal center axis x-x. The relatively thin-stemmed shank 3, which absorbs bending forces, is ensured a stable configuration which provides the resilient flexibility as well as a sufficient thread-guidance cross-section particularly as far as the thread groove 11 is concerned. The groove base 12 is configured as a curved surface W which is located in the transverse direction of the shank 3. This curved surface occupies less than a semicircular arc. The end points of the curved region merge into side flanks 15. The latter diverge and thus provide a widened groove cross-section 16 in the direction of the lateral surface 4. The groove cross-section is greater than the diameter D of the circle-arc-shaped curved contour of the curved surface W. The opening angle between the side flanks 15 is approximately 20 to 30°. The side flanks 15 run in a mirror-symmetrical manner. The diameter D of the circle-arc-shaped curved contour of the curved surface W corresponds substantially to the radius R of the basically cross-sectionally circular shank 3 of the sewing-machine needle 1. The center point of curvature of the curved surface W, which is closed up to form a complete circle in the drawing, is designated y. The circle geometry illustrated, which curves the groove base 12 concavely in the form of an arc, is such that the center point of curvature y is still located within the basic cross-section of the shank 3, but the radius of the circle, depth-wise, has not yet been used up. It is possible to gather the spacing from the center Z. This spacing corresponds substantially to half the radius of the diameter D. The center Z of the shank 3 and the center point of curvature y of the circular curved surface W run in a common longitudinal center plane E-E. Also located on this diameter line, on the other side of the shank 3, for example, is the further thread groove of the double-groove sewing-machine needle 1, which has been designated 13 above. The curved contour of the curved surface W here is configured such that two tangents T which are applied to the curved contour from a point P1 located, in the shank cross-section, on the far side of the center Z of the shank 3 and on the said longitudinal center plane E-E of the shank 3 define a widening-clearance cross-section 17 and an interstice section 18 which is smaller, or, at most, has the same surface area and is located above the tangent-application point 19. Both the widening-clearance cross-section 17, which provides the widened groove cross-section 16 or groove inlet, and the abovementioned interstice section 18 are illustrated in the form of densely hatched areas. A conventional right-angled thread groove has been depicted for comparison. The interstice sections 18 fill the right-angled corners of the old type of thread groove 11 so as to provide concave rounding. Corner notches are thus avoided. In contrast, the widening-clearance cross-section 17 has been cleared away in order to provide a widening groove cross-section 16. The transitions of the side flanks 15, which thus adjoin in a diverging manner, in the direction of the lateral surface 4 may, as illustrated, be convexly rounded. The interstice section 18, on the one hand, is formed by the curved line which rounds the groove base 12, that is to say the curved surface W, and, on the other hand is defined by the tangent T applied in the curvature vertex 19 and the radial line 20 located at right angles (angle alpha) thereto and the straight line G running through the tangent point P1, located parallel to the longitudinal center plane E-E running through the center Z of the shank 3 and the center point of curvature y. Figure 5 shows a comparable geometry in respect of the additional thread groove 13, although in this case the center point of curvature y of the thread groove 13 is offset further in the radially outward direction, remaining in the longitudinal center plane E-E. The center point of curvature y of this curved surface W is located inside the shank, just behind the lateral surface 4, which is conceived as a continuous line. The reference numerals are used analogously without being repeated in the text. In this arrangement, the vertices of the applied tangents T meet in the region of the center axis x-x of the shank, that is to say in the region of the center Z of the shank 3, and can even be seen to overlap. The vertex of the tangents T of the thread groove 13 is designated P2. The overlapping zone U extends, as seen from the thread groove 11, on the far side of the center Z. Nevertheless, the sought-after, widening groove cross-section 16 is also achieved in respect of the thread groove 13. The variant according to Figure 6 has a geometry which is comparable with that which has been already described, at least as far as the parameters of the thread groove 11 are concerned. In contrast, the configuration here has a larger overlapping region U in the longitudinal center plane E-E. The configuration relating to the further thread groove 13 corresponds to that which has been explained in Figure 5. As far as the thread groove 11 is concerned, the tangents T are positioned such that the curvature vertices, in other words tangent-application points 19, are offset from the lower third of the depth of the thread groove 11 approximately to half the depth. The curvature vertices provide a vertex designated by P1, which is offset to a markedly greater extent from the center Z, but is still located within the cross-section of the shank 3. Correspondingly, it is also the case that the areas in respect of the widening-clearance cross-section 17 and of the interstice section 18 are of different sizes. The former has a smaller surface area than the interstice section 18. Nevertheless, the rounding, achieved by the curved surface W, of the transition regions to the side flanks 15 is maintained here. A rather more equal distribution can be gathered from Figure 5. The difference in size of the surface areas of the widening-clearance cross-section 17 and the interstice section 18 is, at most, somewhat less than 30%. Coming back to the variant according to Figure 4, it should also be stated that the thread groove in the form of the supplementary groove 14 there is of markedly smaller cross-section than that discussed in Figures 5 and 6. Since this is considerably less than somewhat smaller than half the circle cross-section, however, the result here is also a mouth width, determined from the contour of the curved surface W, which corresponds approximately to the clear mouth width 16 of the thread groove 11 or 13. While, in the other configurations, the groove borders at the transition from the side flank 15 to the lateral surface 4 are acute-angled, it can be gathered that in the configuration forming the supplementary groove 14 -the groove base is designated 14' - these borders are obtuse-angled (angle beta). As in the basic version, the flanks formed by the extremities of the curved surface W here merge into the lateral surface 4 of the shank 3 via convex rounded border formations. In the case of a single-groove needle, test results have shown that the needle was 10% stiffer in the eye direction and 7% stiffer in the direction transverse thereto. This was a needle which had the lower thread groove 11 described in relation to Figure 5. Tests on a double-groove needle, according to the illustration in Figure 5 resulted in a 25% higher stiffness of the needle body in the eye direction and a 20% higher stiffness of the needle body in the direction transverse thereto. Tests on the type of needle illustrated in Figure 4, that is to say with a thread groove 11 and the supplementary groove 14 explained above, showed a 6% higher stiffness in the transverse direction. The stiffness was 8% lower in the eye direction. All features disclosed are (in themselves) pertinent to the invention. The disclosure content of the associated/attached priority documents (copy of the prior application) is hereby also included in full in the disclosure of the application, also for the purpose of incorporating features of these documents in claims of the present application. WE CLAIM: 1. A sewing-machine needle (1) with a shank (3) which extends from a butt (2) and on its lateral surface - extending from the eye (8) at the needle - point end -has at least one thread groove (11) which runs in the direction of the butt (2) and the groove base (12) of which is configured as a curved surface (W) located in the transverse direction of the shank (3) , the side flanks (15) which belong to the thread groove, and extend from the end point of the curved region, forming a groove cross-section (16) which widens in the direction of the lateral surface (4), characterized in that the diameter (D) of the circle-arc - shaped curved contour of the curved surface (W) is equal to the radius (R) of the shank (3). 2. A sewing-machine needle as claimed in claim 1, wherein the curved contour of the curved surface (W) is adapted such that two tangents (T) , which are applied to the curved contour from a point (P1) located in the shaft cross-section on the far side of the center (Z) of the shank (3) and on the longitudinal center plane (E-E) of the shank (3) (tangent-application point 19), define a widening-clearance cross - section (17) and an interstice section (18) which is smaller, or at most, has the same surface area, is located above the tangent -application point (19) and is formed, on the one hand by the curved line of the curved surface (W) and on the other hand, by the tangent (T) applied in the curvature vertex and the radial line (20) located at right angles (angle alpha) thereto, and the straight line (G) running through the tangent point (19), located parallel to the longitudinal center plane (E-E) running through the center (Z) of the shank (3) and the center point of curvature (y). 3. A sewing-machine needle as claimed in one or more of the preceding claims wherein the difference in size of the surface areas of the widening -clearance cross-section (17) and the interstice section (18) is, at most less than 30%. 4. The sewing - machine needle as claimed in one or more of the preceding claims wherein a supplementary groove (14) which is located opposite the thread groove (11) in a conventional manner, is of smaller cross-section and has a curved base surface (14) and a mouth width approximately equal the clear mouth width (16) of the thread groove (11), the side flanks (15) of the latter running into the lateral surface (4) of the shank (3) at an obtuse angle. 5. The sewing-machine needle as claimed in one or more of preceding claims having two mutually opposite thread grooves (11), with construction as claimed in claim 2, wherein the vertices (P1,P2) of the applied tangents(T) meeting, or even overlapping(U), in the region of longitudinal centre axis (x-x) of the shank(3), in the region of centre(Z). Dated this 25th day of January, 2002. (RANJNA MEHTA DUTT) OF REMFRY & SAGAR ATTORNEY FOR THE APPLICANT(S)

Documents:

abstract1.jpg

in-pct-2002-0105-mum-assignment(28-03-2007).pdf

in-pct-2002-0105-mum-cancelled pages(25-01-2002).pdf

in-pct-2002-0105-mum-claims(granted)-(12-05-2006).doc

in-pct-2002-0105-mum-claims(granted)-(12-05-2006).pdf

in-pct-2002-0105-mum-correspondence(26-04-2007).pdf

in-pct-2002-0105-mum-correspondence(ipo)-(18-04-2006).pdf

in-pct-2002-0105-mum-drawing(22-03-2006).pdf

in-pct-2002-0105-mum-form 18(29-04-2005).pdf

in-pct-2002-0105-mum-form 1a(22-03-2006).pdf

in-pct-2002-0105-mum-form 2(granted)-(12-05-2006).doc

in-pct-2002-0105-mum-form 2(granted)-(12-05-2006).pdf

in-pct-2002-0105-mum-form 3(04-04-2006).pdf

in-pct-2002-0105-mum-form 3(11-05-2006).pdf

in-pct-2002-0105-mum-form 5(25-01-2002).pdf

in-pct-2002-0105-mum-form 6(30-04-2007).pdf

in-pct-2002-0105-mum-form-pct-isa-210(12-05-2006).pdf

in-pct-2002-0105-mum-petition under rule 137(07-04-2006).pdf

in-pct-2002-0105-mum-power of authority(14-02-2002).pdf

in-pct-2002-0105-mum-power of authority(22-03-2006).pdf

in-pct-2002-0105-mum-power of authority(28-03-2007).pdf