JPH09131485A - Threading device for sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operability and accuracy in threading a sewing needle through a hole thereof by a method wherein a thread guide groove part opened to the tip of a hook is formed at the upper and lower positions on the right and on the left centered on the hook and a threading space is formed being continued therefrom. SOLUTION: A hook 23 of a hook part is formed in a plate bent in L near the central part thereof and the tip thereof is formed into a hooked part 51 extending downward. A hook guide part 52 guided into a hole 14a of a sewing needle 14 with the tip thereof formed at an acute angle and a terminal part 53 of the hook and a circular arc-shaped thread contact surface 54 for connecting both the parts 52 and 53 are formed on the hooked part 51. Inclined surfaces 56 and 57 are formed on hook guards 24 and 25 and hence, a V-shaped thread guide part 58 is formed to guide the thread into a thread pulling surface 55. The tips of the hook guards 24 and 25 are made round and bent in the direction of separating from the hook 23. Threading spaces 59 and 60 are formed respectively above and below the hook guards 24 and 25 on both sides of the hook 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a threading device for a sewing machine, and more particularly, in preparation for sewing with a sewing machine,
The present invention relates to a threading device for a sewing machine that allows a thread to pass through the eye of a sewing needle.

[0002]

2. Description of the Related Art Conventionally, as a threading device of a sewing machine, a support shaft provided parallel to a needle bar and rotatable about an axis, and a threading hook (hereinafter, simply referred to as a hook) protruding from the support shaft are provided. The hook is inserted into the eye of the sewing needle by the rotation of the support shaft, and the thread stretched in front of the eye is captured inside the hook hook hand, and after the capture, the hook is rotated by the reverse rotation of the support shaft. It is known that the thread is pulled out from the eyelet and the thread is pulled out from the eyelet of the sewing needle to perform threading (JP-A-63-8).
9194 and Japanese Patent Laid-Open No. 4-64386).

There is also proposed a device in which hook guards are provided on both sides of the hook so that the thread can be caught inside the hook hook hand (Japanese Patent Laid-Open No. 3-126482).
Reference).

The operation of this conventional threading device is shown in FIG.
This will be described with reference to 0 and 11.

As shown in FIG. 10 (A), in the initial state, the threading device 100 stands by at a position above the eyelet 62 of the sewing needle 60. Then, as shown in FIG. 10 (B), the threading device 100 is operated by operating an operation lever (not shown) so that the hook portion 72 of the hook 70 and the eye hole 62 of the sewing needle 60 can be operated.
The supporting shaft 80 is moved down by a predetermined distance to a position where the horizontal positions of the supporting shaft 8 and the horizontal position of the supporting shaft 8 are the same, and thereafter, as shown in FIG.
The hook 70 penetrates into the eye hole 62 of the sewing needle 60 by rotating around 0. This hook 70 is the eyelet 6 of the sewing needle 60.
11 (A) to FIG. 1 in the process of approaching / penetrating
As shown in FIG. 1 (C), the thread T stretched near the back surface of the eye 62 of the sewing needle 60 (the thread T is in a tensioned state) is introduced into the thread introduction groove 78 of the hook guards 74 and 76. .

At this time, if the thread T is out of the center of the eye hole 62 of the sewing needle 60, the thread T is pulled by the hook guard 74,
It contacts the inclined surface 82 or the inclined surface 84 of 76, slides in the direction of arrow e or arrow f, and contacts the thread contact surface 86 of the hook portion 72 of the hook 70. At this time, the tensioned thread T is
It bends downward or the hook 70 is elastically inclined in the direction of arrow d, and slides on the thread contact surface 86 in the direction of arrow c,
It rides over the tip 88 of the hook and comes into contact with the thread-pulling surface 90 which is the inside of the hook. At this position, the rotation of the support shaft 80 is stopped, and the hook portion 72 of the hook 70 locks the thread T.

Next, the thread T is loosened, the hook 70 is retracted from the eyelet 62 of the sewing needle 60 by the reverse rotation of the support shaft 80, and the threading device 100 is returned to the initial position by the upward movement of the support shaft 80. As a result, the thread T is pulled out from the eye hole 62 and threading is completed.

[0008]

However, when the thread T is guided to the hook portion 72 of the hook 70, the hook hand tip portion 88 of the hook 70 and the inclined surface 84 of the hook guards 74 and 76 are shown in FIG.
As shown in FIG. 1 (A), as the diameter of the thread T increases, the resistance increases due to the bending of the thread T when entering the inside of the hook as the diameter of the thread T increases, as shown in FIG. 1 (A). However, a large tension was required for the yarn T. Therefore, when the thread T is stretched in the vicinity of the back surface of the eye hole 62 of the sewing needle 60, as shown in FIG. Of course, for those who are unfamiliar with the operation, the threading operation had to be repeated many times due to an operation error. FIG.
As shown in (B), when the thread tensioning mechanism 112 provided in the threading device 110 is used, the thread T becomes insufficient in tension due to the resistance received from the hook 70 and the hook guards 74 and 76, and is guided to the hook portion 72. I was making an operation mistake.

Further, the greater the tension at which the thread T is stretched, the greater the deformation of the hook 70 shown in FIG. 11 (B) in the direction of the arrow d, which may cause damage to the hook 70 itself.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to improve operability and certainty in threading the needle through the eye hole.

[0011]

In order to achieve this object, the invention according to claim 1 is such that a hook hand extending downward is formed at the tip and stretched on the back surface of the eye of the sewing needle. A hook for threading, a support that supports the hook and rotates and moves at least so that it can penetrate into and out of the eye of the sewing needle, and two sheets that are supported by the support and that are apart from the hook by a predetermined distance. In a threading device for a sewing machine provided with a plate-shaped hook guard, a thread introduction groove portion opened toward the tip end direction of the hook at left and right upper and lower positions around the hook, and a continuous thread introduction groove portion. Formed,
A threading device for a sewing machine having a thread passing space for allowing the thread to enter.

According to the threading device for a sewing machine of the present invention having the above-mentioned structure, first, the thread stretched on the back surface of the eye of the sewing needle is introduced into the thread introducing groove portion of the hook guard, and the thread is introduced into the inner surface of the thread introducing groove portion. It is guided and touches the hook's hook. Subsequently, the thread that abuts the hook hook hand slides in the distal direction of the hook hand that extends downward due to the tension, is guided by the hook and hook guard, and passes through the thread passing space. It gets over the tip of the hook and is locked in the hook.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a threading device for a sewing machine according to this embodiment, and FIG. 2 is an exploded perspective view showing a part thereof. The upper shaft 1 is configured to be rotationally driven by a sewing machine motor (not shown), and a counterweight 2 attached to the upper shaft 1 is provided with a crank pin 4 which is rotatably mounted on the crank pin 4. One end of the crank rod 6 is inserted as possible. Further, the other end of the crank rod 6 has a needle bar holder 8
Is rotatably inserted, and this needle bar holder 8 has a needle bar 1
It is fixed to 0.

The needle bar 10 is supported on a needle bar base 11 so as to be slidable in the vertical direction, and a sewing needle 14 is supported at the lower end of the needle bar 10 by a needle holder 12 and a tightening screw 13. . A thread guide 16 that guides a thread 15 (see FIG. 4 and subsequent figures) into the eye hole 14 a of the sewing needle 14 is attached near the needle clamp 12. Further, a positioning stopper 17 is fixed to the needle bar 10 by a set screw 18 at a predetermined position above the needle bar holder 8. The positioning stopper 17 is formed with a stopper surface 17a that is orthogonal to the axial direction of the needle bar 10.

On the needle bar base 11, a threading bar 19 is further provided parallel to the needle bar 10 so as to be rotatable about its axis and slidable in the vertical direction. And
A threading device 20, which will be described later, is provided at the lower end of the threading rod 19.

On the other hand, on the upper side of the threading rod 19, as shown in FIG. 3, an operating pin 21 is inserted and fixed so as to penetrate the threading rod 19 in the axial direction. This operating pin 21
When the threading rod 19 is lowered, it is made to abut against the stopper surface 17a of the positioning stopper 17, and at the time of abutment, the hook 2 of the hook portion 22 to be described later will be described.
3 and the eye 14a of the sewing needle 14 have the same height, the positioning stopper 17 attaches to the needle bar 10 with the set screw 1
8 fixed.

A hollow operating punch 26 is slidably inserted into the threading rod 19, and a compression spring 27 is interposed between the operating pin 21 and the operating punch 26. As shown in FIG. 2, a guide groove 28 extending upward in an arc shape along the outer periphery is formed on the outer periphery of the operating punch 26, and one end of the operating pin 21 is engaged with the guide groove 28. It is designed to meet.

A threading rod 19 is provided at the upper end of the operating punch 26.
Is formed on the outer periphery of the operating punch 26, and is formed integrally with the spring hooking portion 30 and a moving base 31 described later. A spring 32 is stretched between a spring hook (not shown),
The operating pestle 26 is biased upward. Needle bar base 11 slidably supporting a threading rod 19 in which an operating punch 26 is inserted.
As shown in FIG. 1, one end of an L-shaped support shaft 33 is rotatably inserted into the upper end of the support shaft so as not to come off. The other end of the support shaft 33 is attached to a sewing machine frame (not shown). It is inserted into the fixed threading support frame 34 so as to be rotatable and prevented from coming off by the set screw 3. And the threading support frame 3
A guide rod 35 is fixed to the thread 4 in parallel with the threading rod 19, and a movable base 31 provided separately from the operating punch 26 is slidably inserted in the guide rod 35.

A groove 36 is formed in the moving base 31 along the sliding direction, and a pin 37 provided upright on the guide rod 35 is engaged with the groove 36 to slide the moving base 31. In case of, the rotation is stopped. Further, on the upper end of the moving table 31, the contact portion 29 when protruding in the direction of the operating punch 26 and sliding.
Is formed with a protrusion 38 that can abut. In this embodiment, the movable table 31 is assembled so that the predetermined distance L is formed between the protrusion 38 and the contact portion 29 when the movable table 31 is at the uppermost position shown in FIG. It is possible to implement even if the protrusion 38 and the contact portion 29 are in contact with each other without forming the predetermined distance L.

The movable table 31 is provided with a rack portion 39 having teeth formed in the sliding direction. A pinion gear 40, which is rotatably supported by the threading support frame 34, is meshed with the rack portion 39. The pinion gear 40 is integrally formed with a helical gear 41, and the helical gear 41 is meshed with a worm gear 43 attached to a rotary shaft of a pulse motor 42 attached to the threading support frame 34. Has been done. The worm gear 43, the helical gear 41, the pinion gear 40, and the rack portion 39 constitute a transmission mechanism 44.

With the above structure, when the pulse motor 42 of the transmission mechanism 44 is rotationally driven, the movable table 31 is slid downward, descends the predetermined distance L, and the protrusion 3 of the movable table 31 is moved.
8 comes into contact with the contact portion 29 of the operating pestle 26 to lower the operating pestle 26. Due to the lowering of the operating punch 26, the compression spring 2
7, the threading rod 19 is lowered through the guide groove 28 and the operating pin 21, and as the threading rod 19 is lowered, the threading device 20
Is also dropped.

As the threading rod 19 descends, the operating pin 21
Is lowered, and the other end of the operating pin 21 is positioned by the positioning stopper 1
7 to the stopper surface 17a. At this time, since the rotation of the upper shaft 1 is stopped, the needle bar 10 is fixed via the crank rod 6 and the needle bar holder 8 to prevent the threading bar 19 from further descending. When the moving table 31 is further lowered and the operating punch 26 is lowered while the lowering of the threading rod 19 is restricted, the operating punch 26 is lowered against the urging force of the compression spring 27, and at that time The operating pin 21 moves along the groove 28. That is, the threading rod 19 is rotated via the operating pin 21 by the lowering of the guide groove 28. The rotation of the threading rod 19 causes the threading device 20 to perform a predetermined operation as shown below, and the eyelet 14a of the sewing needle 14 is caused.
Pass thread 15 through.

As shown in FIG. 4, the threading device 20 for threading the thread 15 through the eye hole 14a by rotating the threading bar 19 is provided.
With the rotation of the threading rod 19 in the direction of the arrow YA, the thread 1
A link mechanism 45 that stretches the thread 5 on the front surface of the eye hole 14a and a hook portion 22 that rotates together with the threading rod 19 and is swung toward the back surface of the eye hole 14a of the sewing needle 14 are provided.

The link mechanism 45 includes a first link portion 45a which rotates together with the threading rod 19, a second link portion 45b which is rotatably supported by the threading rod 19, first and second link portions 45a, 45a. The third and fourth link portions 45c and 45d are provided between the third and fourth link portions 45c and 45b. A connecting pin 45e for connecting the third and fourth link portions 45c and 45d is rotatably fitted on the lower end of the threading rod 19 and is slidable in the vertical direction by the needle bar support frame. It is slidably fitted in a sliding groove 46a formed in the supported link guide 46.

The link mechanism 45 includes the third and fourth link portions 4
5c and 45d are connected to each other, and the thread gripping portion 47 that grips the end portion of the thread 15 with a predetermined pressure, and the second link portion 45.
The thread locking portion 48 formed at the end of b and connecting the first and third link portions with the thread locking portion 48 that locks the thread 15 that has passed through the thread guide 16 is formed. 47 and a yarn holding portion 49 for holding the yarn, which is provided between
These are configured such that when the threading rod 19 is rotated in the direction of the arrow YA, as shown in FIG. 5, the thread 15 is stretched over the front surface of the eye 14a of the sewing needle 14 for a predetermined length. .

Next, the hook portion 22, which is a characteristic configuration of the present invention, will be described.

The hook portion 22 is composed of a hook 23 and hook guards 24 and 25, and is fixed to a support base 50 formed on the first link portion 45a of the link mechanism 45 as shown in FIG. The central portion is a plate shape bent into an "L" shape, and a hand-shaped hook portion 51 of a hook extending downward is formed at the tip thereof. This hook 51
As shown in FIG. 7, the sewing needle 1 has a sharp tip.
Hook introduction portion 52 introduced into the fourth eye hole 14a, hook hand tip portion 53 formed at an acute angle with the hook hand tip, and hook introduction portion 5
2 has a thread contact surface 54 formed in an arc shape connecting the hook hand tip portion 53, and an "L" -shaped thread drawing surface 55 is formed inside the hook hand. ing.

The hook guards 24 and 25 are parallel to the hook 23, and the hook guard 24 is located inside and below the hook 23 with respect to the threading rod 19 which is the rotating shaft.
Reference numeral 5 denotes a plate-like member located outside and above the hook 23, and has inclined surfaces 56 and 57 with respect to the projecting direction, and the hook portion 22 is provided with two hook guards 24 and 25 when viewed from the side.
The inclined surfaces 56 and 57 of the No. 3 form a thread introduction groove portion 58 in a “V” shape so as to guide the thread 15 to the thread drawing surface 55.
Further, the hook guard 2 corresponding to the entrance of the thread introducing groove 58
The tip portions of 4, 25 have a rounded shape, and are bent in a direction of separating from the hook 23. And
Threading spaces 59 and 60 are provided on both sides of the hook 23 above the hook guard 24 and below the hook guard 25.

Further, the hook 23 and the hook guards 24, 2
The positional relationship of 5 is that the hook 23 and the hook guards 24 and 25 are
When viewed from the direction perpendicular to the plate surface (the direction of the arrow X in FIG. 7), the hook 23 is arranged so as to be located substantially in the center between the hook guard 24 and the hook guard 25, and the hook of the hook 23 is disposed. The thread contact surface 54 and the thread pulling surface 55 of the portion 51 are located between the grooves of the thread introducing groove portion 58 formed by the hook guards 24 and 25, and the hook introducing portion 52 of the hook 23 and the hand tip portion 53 of the hook are respectively formed. It is hidden behind the hook guards 25, 24. The distance between the hook 23 and the hook guard 25 is equal to the radius of the sewing needle 14 at the position of the eye hole 14a, and the distance between the hook 23 and the hook guard 24 is set larger than the radius.

Next, the hook 23 and the hook guard 2
The operation of Nos. 4 and 25 will be described with reference to FIGS.

The transmission mechanism 44 lowers the threading rod 19 by a predetermined distance to a position where the hook portion 51 of the hook 23 and the eye hole 14a of the sewing needle 14 become horizontal, and then the threading rod 19 is moved. When the hook 23 and the hook guards 24 and 25 rotate around the threading rod 19, the inner side surface of the hook guard 25 comes into contact with the side surface of the sewing needle 14 and slides on the side surface. Sewing needle 14
The hook 23 is positioned with respect to the eye hole 14a,
The hook 23 penetrates the eye hole 14a of the sewing needle 14. In the process in which the hook 23 approaches / penetrates the eye 14a of the sewing needle 14, the thread 15 (thread 15 in a tensioned state) stretched in the vicinity of the back surface of the eye 14a of the sewing needle 14 is hooked by the hook guards 24, 25. The yarn is introduced into the yarn introduction groove portion 58. At this time, when the thread 15 is out of the center of the eye hole 14 a of the sewing needle 14, the thread 15 is slid on the inclined surface 56 of the hook guard 24.
Alternatively, it contacts the inclined surface 57 of the hook guard 25 and slides on the inclined surfaces 56 and 57 in the arrow j or arrow k direction.

Subsequently, the thread 15 sliding on the inclined surface 56 or the inclined surface 57 contacts the thread contact surface 54 of the hook portion 51 of the hook 723. At this time, the tensioned thread 15 is urged in the right direction in the drawing by the approaching / penetrating motion of the hook 23. Therefore, the thread 15 bends downward as shown in FIG. Thread 15 under the guard 25
Has the thread passing spaces 59 and 60 so as to easily get over the hand end portion 53 of the hook, so that the thread contact surface 54 with a small resistance.
Slide in the direction of the arrow l, get over the tip 53 of the hook and come into contact with the thread-pulling surface 55, which is the inside of the hook. At this position, the rotation of the threading rod 19 is stopped, and the hook portion 51 of the hook 23 locks the thread 15.

Next, the threading completion operation of the threading device of the present embodiment will be described with reference to the drawings.

In the state shown in FIG. 5, the pulse motor 4
When 2 is reversed and the threading rod 19 is rotated in the direction of the arrow YB, the hook portion 22 and the second link portion 45b move in the direction of separating from each other, and the hook 23 hooks the thread 15. Escape from the eyelet 14a. Then, from this state, the threading rod 1
9 further rotates in the YB direction, and before the hook 9 rotates in the arrow YA direction, that is, in the initial state, the hook 23 pulls the thread 1
5, while retracting, the thread 15 is pulled out from the eyelet 14a, and the threading rod 19 is raised to the initial position to complete threading.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments and can be implemented in various modes without departing from the scope of the present invention. Of course.

[0037]

As is apparent from the above description, according to the threading device of the first aspect, when the thread passes over the hand tip of the hook and is guided to the thread pulling surface, the bending resistance is caused by the hook and the hook guard. Even if the yarn is received, the yarn can pass through the yarn passing space to reduce the resistance and facilitate the introduction of the yarn into the hook portion. As a result, when the operator pulls the thread on the back surface of the eye of the sewing needle with the finger, it is not necessary to intentionally increase the thread tension in the thick thread, and the operability is improved.

When the thread is tensioned by the thread tensioning mechanism arranged in the threading device, the thread tensioning mechanism is not required to adjust the thread tensioning tension with respect to the diameter of the thread, and the thread can be reliably guided with a simple structure. Comes out. Further, since it is not necessary to increase the thread tension on the thick thread, when the thread goes over the tip end of the hook, the hook is not largely deformed, and the hook can be prevented from being damaged.

[Brief description of the drawings]

FIG. 1 is a perspective view of a threading device for a sewing machine as an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a part of the threading device of the present embodiment.

FIG. 3 is a partial perspective view near the positioning stopper according to the present embodiment.

FIG. 4 is a plan view of a main part of the threading device of the present embodiment.

FIG. 5 is a plan view of an essential part of the threading device of the present embodiment.

FIG. 6 is a plan view of an essential part of the threading device of the present embodiment.

FIG. 7 is a side view of a hook portion according to the present embodiment.

FIG. 8 is an operation explanatory view of the essential parts of the threading device of the present embodiment.

FIG. 9 is a front view of a hook portion according to the present embodiment.

FIG. 10 is an operation explanatory view of the conventional threading device.

FIG. 11 is a diagram for explaining the operation of the conventional hook portion.

FIG. 12 is an explanatory view showing a conventional threading device.

FIG. 13 is a front view of a conventional hook portion.

[Explanation of symbols]

 14 Sewing needle 14a Eye hole 15 Thread 19 Threading rod 22 Hook part 23 Hook 24,25 Hook guard 51 Hook part 53 Hook hand tip part 58 Thread introduction groove part 59,60 Thread passing space

Claims (1)

[Claims] 1. A hook for threading, which is formed at a tip end of a hook extending downward and catches a thread stretched on the back surface of the eye hole of a sewing needle, and a hook which supports the hook and is provided at least in the eye hole of the sewing needle. A threading device for a sewing machine, comprising: a support member that is rotatably moved so that it can be inserted and removed; and a plate-shaped hook guard that is supported by the support member and that sandwiches the hook and faces the hook at a predetermined distance. It is characterized in that it has a thread introduction groove portion opened toward the tip direction of the hook at left and right upper and lower positions, and a thread passing space formed continuously from the thread introduction groove portion for allowing the thread to enter. Sewing machine threading device.