US3699911A

US3699911A - Self-threading needle

Info

Publication number: US3699911A
Application number: US193820A
Authority: US
Inventors: Stanley J Ketterer
Original assignee: Singer Co
Current assignee: SINGER SPEZIALNADELFABRIK A CORP OF WEST GERMANY GmbH; SSMC Inc
Priority date: 1971-10-29
Filing date: 1971-10-29
Publication date: 1972-10-24
Anticipated expiration: 1989-10-24

Abstract

A sewing machine is disclosed in which a threading slot is provided along the needle blade and opening into the needle eye. This needle, which may be fabricated using conventional milling and grinding machinery, provides a self-threading needle eye construction which will deter re-entry of the thread into the threading slot once the thread has been drawn into the needle eye.

Description

United States Patent Ketterer [s41 SELFQTHREADING NEEDLE [4 1 Oct. 24, 1972 2,178,607 11/1939 Rainville ..l12/224 2,273,592 2/ 1942 Rainville ..1 12/224 2,539,859 l/195l Rainville ..1 12/224 2,767,670 10/ 1956 Surbeck ..1 12/ 224 Primary Exantiner-Wemer l-l. Schroeder Attorney-Marshall J. Breen et a1.

[57] ABSTRACT A sewing machine is disclosed in which a threading slot is provided along the needle blade and opening into the needle eye. This needle, which may be fabricated using conventional milling and grinding machinery, provides a self-threading needle eye construction which will deter re-entry of the thread into the threading slot once the thread has been drawn into the needle eye.

4 Claims, 7 Drawing Figures SELF-THREADING NEEDLE BACKGROUND OF THE INVENTION under certain sewing conditions the thread can re-enter the threading slot and escape from the needle eye.

BRIEF SUMMARY OF THIS INVENTION It is an object of-this invention to provide a selfthreading sewing machine needle which includes a threading slot extending along the needle blade and opening into the needle eye, which can be manufactured using conventional milling and grinding machinery, and which will provide a needle eye construction into which the thread once introduced is deterred from being drawn back up the threading slot during sewing operations.

These objects of this invention are attained by a needle construction in which a groove of uniform cross sectional configuration is milled lengthwise along the needle blade, and a resilient tongue attached as by welding to the point of the needle is constrained in the groove. The eye of the needle is formed by an outwardly open transverse notch formed in the needle blade and a contiguous inwardly open transverse notch formed in the resilient tongue. By making the notch in the needle blade shallower than the lengthwise groove, the thread once in the needle eye will be prevented from re-ent'ering the threading slot from the inside, and by forming the notch in the needle blade so as to extend closer to the needle shank than the notch in the resilient tongue, the thread will traverse the abutting edges of the needle blade and the resilient tongue at such a flat angle regardless of the direction of sewing that the thread cannot be drawn into the threading slot from the outside.

DESCRIPTIONOF THE DRAWINGS FIG. 1 represents an elevational view of a sewing machine needle embodying this invention as viewed from a position looking through the needle eye,

FIG. 2 represents an elevational view taken from the right-hand side of the needle of FIG. 1,

FIG. 3 is an enlarged cross sectional view of the needle taken substantially along line 3-3 of FIG. 1,

FIG. 4 is an enlarged cross sectional view of the needle taken substantially along line 4-4 of FIG. 1,

FIG. 5 is an enlarged cross sectional view of a modified form of the needle taken substantially along line 44 of FIG. 1,

FIG. 6 is an enlarged perspective view of a fragment of the needle of FIGS. 1 and 2 in the vicinity of the needle eye and showing a thread loop passing through the needle eye, and

FIG. 7 is an elevational view of that portion of the needle shown in FIG. 6, including the thread loop passing through the needle eye.

As illustrated in the drawing, the needle of this invention is formed with a cylindrical shank 11 which may be slabbed as at 12 for orientation in a sewing machine needle clamp. From the shank, the needle tapers to a cylindrical blade portion 13 which at the opposite end from the shank is formed with a pointed extremity 14.

The needle blade is formed lengthwise with a groove 15 of uniform cross sectional shape extending from the pointed extremity 14 to the needle shank 11. As shown in FIGS. 3 and 6, the groove 15 is preferably formed by a rotary milling cutter and includes a bottom wall 16 and a side wall 17 extending at right angles to the bottom wall. Preferably, the bottom wall 16 of the groove l5 includes a recessed portion 18 adjacent to the side wall 17. The groove 15 occupies approximately one quadrant of the cross sectional area ofv the cylindrical needle blade 13 and defines a forwardlyv extending fin 19 of the needle blade which also comprises substantially a quadrant of the needle cross section.

A resilient tongue 30 preferably of uniform rectangular cross sectional shape is arranged in the groove 15. The tongue 30 includes one flat side wall 31 arranged contiguous to the side wall 17 of the groove 15. The tongue also includes an inside edge 32 extending within the recess 18 and an outside edge 33 substantially flush with the front edge of the fin 19 on the needle blade. The tongue 30 extends from the pointed extremity 14 to the needle shank 1 1 and at the needle shank, the tongue terminates in an inclined extremity 34. The needle shank is formed with a shallow transverse notch 35 which exposes the tip of the inclinedextremity 34 of the tongue to provide for introduction of thread thereto as is shown in FIGS. 1 and 2.

As shown in the drawings the resilient tongue 30 is formed with a transverse notch 40 which defines the needle eye. The notch 40 is open to the inside edge 32 of the tongue which extends into the recess 18 in the bottom wall of the groove 15. The resilient tongue 30 is secured to the needle blade as by a weld from the lower wall 41 of the notch 40 to the pointed extremity 14 of the needle. Above the upper wall 42 of the notch 40, the resilient tongue is not attached to the needle blade and thus when the thread is introduced between the needle blade and the tongue as shown in FIGS. 1 and 2, it may be drawn downwardly between the tongue and the needle blade into the notch '40 in the tongue 30 which defines the needle eye.

The fin 19 of the needle blade is formed with a transverse notch 50 disposed opposite the notch 40 in the resilient tongue. The bottom wall 51 of the notch 50 is preferably flush with the bottom wall 16 of the groove 15 and proud of the recess 18 as shown in FIG. 4 thus providing for an overlapping relation with the inside edge 32 of the tongue so that the thread once drawn into the notch 40 in the resilient tongue 30 will be prevented from escaping out of the notch 40 in the direction of the bottom wall 16 of the groove 15.

FIG. 5 illustrates a modification of the shape of the groove 15 and the shape of the notch 50 in which the groove 15 is formed without the recessed portion 18. With this modified arrangement, in order to provide for an overlapping relation of the inside edge of the tongue 30 by the needle blade to prevent egress of thread from the notch 40 in the direction of the bottom wall 16 of the groove, the notch 50 is made shallower than the bottom wall 16 of the groove 15, Therefore, in the modification shown in FIG. 5, the bottom wall 51' of the notch 50 is proud of the bottom wall 16 of the the lower wall 52 of the notch 50 in the fin 19 is disposed substantially coplanar with the lower wall 41 of the notch 40 in the resilienttongue 30. The upper wall 53 of the notch 50, however, is spaced considerably above the notch 40. As indicated in FIG. 7 the notch 50 is preferably formed at least twice the dimension lengthwise of the needle blade in comparison with the notch 40 and as a result, a limb of thread Tw extending from the notch 40 will be inclined about the upper wall 53 of the notch 50 at an obtuse angle asshown FIGS. 6 and 7 and only small forces can be generated tending to draw the thread into the space between the fin l9 and the resilient tongue 30.

it will be appreciated that the portion of the groove not occupied by the tongue 30 provides a thread accommoda ting groove along the needle blade corresponding to what is referred to in the sewing machine art as the long groove of a conventional sewing machine needle. The limb of thread Ts which extends from the needle eye and occupies the groove 15 is the thread which extends to the supply spool. The other limb Tw of the loop of thread through the needle eye extends to the previous stitching in the work. This limb of thread Tw finds no sheltering groove in the needle and will, therefore, be formed readily into a loop during upstroke of the needle to encourage needle thread seizure by the sewing machine loop taker; Depending upon the direction of feed of the work anddepending upon the direction of lateral jogging of the needle, the work limb Tw of the thread maybe wrapped in various ways around the needle blade. The danger of accidental unthreading of the needle eye is greatest when the work limb Tw of the thread is wrapped as shown in FIGS. 6 and 7 across the outside edge of the transverse notch 50 in the needle blade fin 19. The location of the upper wall 53 of the notch 50 above the upper wall 42 of the notch 40 in the resilient tongue-30 gives rise to the favorably shallow or obtuse angle which the work limb Tw is caused to take in these circumstances. As a result it is practically impossible for sufficient force to be generated by tension in the work limb Tw to cause The needle of this invention, moreover, may be manufactured conveniently without requiring vspecial tools or special machining operations. The groove 15 may be cut with a conventional milling cutter, the needle blade and resilient tongue may be fabricated by conventional methods, and the parts may be united by sim le w ldin s after t e transverse n tche have been machined m the parts by conventiona machining operations.

Having set forth the nature of this invention, what is claimed herein is: a

l. A s'elf-threading sewing machine needle including a shank adapted to be clamped to the sewing machine, a cylindrical blade extending from the shank and terminating in a pointed extremity, said cylindrical blade being formed with a straight lengthwise groove of substantially uniform cross sectional shape defining side the thread to become wedged between the tongue 30 of the tin 19 of the needle blade.

The configuration of the needle of this invention in the vicinity of the needle eye, therefore, provides an effective deterrent to unthreading of the needle either by the thread inadvertently wedging between the tongue and the needle blade toward the inside or toward the outside thereof. The configuration of the needle in the vicinity of the needle eye, however, does not impose any deterrent to easy introduction of the thread downwardly between the tongue 30 and the needle blade, and therefore, the needle of this invention provides for ready introduction of the thread with minimum chance of accidental unthreading.

walls along said needle blade, an elongate resilient tongue arranged with said needle blade groove and extending lengthwise of said needle from said pointed extremity to said shank, means securing said resilient tongue to said needle blade adjacent to said pointed extremity in a position against one side wall of said needle blade groove, said tongue being formed with an in wardly open transverse notch, the side wall of said needle blade against which said tongue is disposed being formed with an outwardly open transverse notch, said notches being arranged in alignment one with the other to define a needle eye, said tongue extending deeper into said needle blade groove than the depth of said transverse notch in said needle blade side wall, and said transverse notch in said needle blade side wall extending toward said needle shank a distance appreciably greater than said transverse notch in said resilient tongue.

2. A self-threading sewing machine needle as set forth in claim 1 in which both said lengthwise groove and said transverse notch in said needle blade are formed to the same depth and a recess is formed in said lengthwise groove to accommodate said resilient tongue extending deeper than the depth of said transverse notch in said needle blade side wall.

3. A self-threading needle as set forth in claim 1 in which the notch in said resilient tongue and the notch in said needle blade side wall are formed with substantially coplanar lower walls, and in which the outwardly open notch in said needle blade side wall extends in a direction lengthwise of said needle blade a distance at least twice that of said inwardly extending notch in said resilient tongue.

4. A self-threading needle as set forth in claim 1 in which said needle blade groove occupies substantially one quadrant of the cross section of said needle blade and defines said walls which diverge at substantially right angles to each other, and in which said resilient tongue occupies only a portion of said needle blade groove.

a a: e

Claims

1. A self-threading sewing machine needle including a shank adapted to be clamped to the sewing machine, a cylindrical blade extending from the shank and terminating in a pointed extremity, said cylindrical blade being formed with a straight lengthwise groove of substantially uniform cross sectional shape defining side walls along said needle blade, an elongate resilient tongue arranged with said needle blade groove and extending lengthwise of said needle from said pointed extremity to said shank, means securing said resilient tongue to said needle blade adjacent to said pointed extremity in a position against one side wall of said needle blade groove, said tongue being formed with an inwardly open transverse notch, the side wall of said needle blade against which said tongue is disposed being formed with an outwardly open transverse notch, said notches being arranged in alignment one with the other to define a needle eye, said tongue extending deeper into said needle blade groove than the depth of said transverse notch in said needLe blade side wall, and said transverse notch in said needle blade side wall extending toward said needle shank a distance appreciably greater than said transverse notch in said resilient tongue.