JP3486940B2 - Threader for needle hole of sewing machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention of the present application relates to a threading device for a sewing machine needle hole, and in particular, it is attached to an arm of a sewing machine having an upper stopping function of a sewing machine needle and reciprocally rotated between a use position and a standby position. The present invention relates to a threading device for sewing machine needle holes.

[0002]

2. Description of the Related Art As a conventional device of this type, for example, there is one described in JP-A-2-104391.
In this conventional device, a hook that is taken in and out from one side of a needle hole of a sewing machine needle fixed to a needle bar is fixed to a swing arm,
This swing arm is attached to the sewing machine arm so that it can be reciprocally rotated about the horizontal axis in the left-right direction between the use position and the standby position that does not interfere with sewing work, and the swing arm is used from the standby position when threading. Rotate to the position to pass the hook through the needle hole, hook the thread on the hook protruding from the needle hole, and then rotate the swing arm from the use position to the standby position to put the thread hooked on the hook into the needle hole. I am trying to pass it. The height of the hook is constant when the swing arm is in the use position, but the height of the needle hole when the sewing machine is stopped varies slightly, and the swing arm is in the standby position when the needle hole does not match the hook height. Since the hook is damaged by the collision with the sewing machine needle when it is rotated from the position to the use position, the swing arm is allowed to rotate from the standby position to the use position only when the height of the needle hole matches the height of the hook. If the height of the hole does not match the height of the hook, even if the swing arm is rotated from the standby position toward the use position, a lock that prevents the swing arm from rotating before the hook collides with the sewing machine needle. The attachment of a mechanism prevents damage to the hook.

[0003]

However, in the above-mentioned conventional apparatus, it is necessary to adjust the needle hole height to a predetermined height by positioning the needle bar at a predetermined position after the sewing machine is stopped, which results in high work efficiency. It is an obstacle to improvement.

An object of the invention of this application is to provide a threading device for a sewing machine needle hole which does not require a positioning operation of a needle bar during threading.

[0005]

The invention of this application is focused on that the height of the needle hole is constant with respect to the lower end surface of the needle bar, and in order to achieve the above object, the invention is fixed to the needle bar. A hook that is inserted into and removed from the needle hole of the sewing machine needle from one side is fixed to a guide, and this guide is supported by a swing arm so that it can move vertically, and this swing arm is centered on the horizontal axis in the front-back direction with respect to the sewing machine arm. An urging member that is mounted so as to be reciprocally rotatable between a use position and a standby position, and is provided with an urging member that urges the guide upward. And a threading device for a sewing machine needle hole, which is provided with a horizontal positioning portion capable of contacting the peripheral surface of the sewing machine needle.

In order to facilitate the threading operation, the guide is needled while elastically applying a predetermined tension to the thread in the process of pulling out the thread hooked on the hook through the needle hole together with the hook from the needle hole. It is preferable to provide a thread hooking elastic member for feeding into the hole.

Further, in order to smoothly and surely match the positions of the hook and the needle hole, the vertical positioning portion and the horizontal positioning portion extend horizontally from the upper end of the guide toward the sewing machine needle. It is preferable that the fork is a bifurcated body that is made to exist and is bent at the tip end portion so as to sandwich the sewing machine needle, and the interval between the tip end portions is gradually increased toward the tip end.

Further, the horizontal shaft is supported by a mounting bracket that is detachable from the sewing machine arm so that the horizontal shaft can be purchased and installed in the sewing machine at a necessary time after purchase.
The swing arm has a circular arc surface centered on the horizontal axis and a concave portion located on the circular arc surface, and a leaf spring having a convex portion formed at its free end for press-contacting the circular arc surface is attached to the mounting bracket. Preferably, the concave portion and the convex portion are engaged with each other and held in position at the standby position of the swing arm.

[0009]

In the sewing machine needle threading device configured as described above, when the swing arm is rotated from the standby position to the use position, the vertical positioning portion of the guide to which the hook is fixed has the lower end surface of the needle bar. To position the hook at a constant height with respect to the lower end surface of the needle bar, and the horizontal positioning portion of the swing arm abuts the peripheral surface of the sewing machine needle so that the horizontal position of the hook is aligned with the sewing machine needle. Position relative to. Since the height of the needle hole of the sewing machine needle is constant with respect to the lower end surface of the needle bar, the height of the hook exactly matches the height of the needle hole. Further, since the horizontal position of the needle hole of the sewing machine needle is constant with respect to the sewing machine needle, the horizontal position of the hook exactly matches the horizontal position of the needle hole. Therefore, even if the height of the needle hole when the sewing machine is stopped varies to some extent, the hook can be accurately inserted into the needle hole simply by rotating the swing arm from the standby position to the use position. Thereafter, as in the conventional device, the thread is hooked on the hook protruding from the needle hole, and the swing arm is rotated from the use position to the standby position to pass the thread through the needle hole. Therefore, the operation of adjusting the height of the needle hole unlike the conventional device is unnecessary, and the work efficiency can be improved.

Hook the thread on the hook protruding from the needle hole,
When the swing arm is rotated from the use position to the standby position, the tip side of the thread is fed while giving an appropriate thread tension in response to the thread being pulled into the needle hole by the hook. It is quite difficult to give an appropriate thread tension with. By providing a thread hooking elastic member for feeding the thread hooked on the hook passed through the needle hole into the needle hole while applying a predetermined tension to the thread in the process of pulling out the thread from the needle hole with the hook in the guide, This manual work can be omitted, and the threading action can be made easier.

Further, the vertical positioning portion and the horizontal positioning portion extend horizontally from the upper end of the guide toward the sewing machine needle while the swing arm is in the use position, and the tip portion. Is a bifurcated body formed by bending the sewing machine downward so as to sandwich the sewing machine needle, and the tip portion of the bifurcated body is formed by the bifurcated body in which the interval between the tip portions is gradually increased toward the tip. Since it acts as a guide when abutting against the rod and the sewing machine needle, the hooks will not be affected regardless of variations in relative positions of the components mounted on the sewing machine arm due to dimensional accuracy and assembly accuracy of the components. The positions of the needle holes can be smoothly and surely matched.

Further, the horizontal shaft is supported by a mounting bracket which is attachable to and detachable from the sewing machine arm, and the swing arm is provided with an arc surface centered on the horizontal shaft and a recessed portion located on the arc surface. , A leaf spring having a free end formed with a convex portion that comes into pressure contact with the circular arc surface is fixed to the mounting bracket, and the concave portion and the convex portion are engaged and held at the standby position of the swing arm. By doing so, the sewing machine can be purchased and installed in the sewing machine at a necessary time after the purchase.

[0013]

Embodiments of the invention of this application will be described with reference to the drawings.

1 to 4, 10 is a sewing machine arm of a single-needle lockstitch automatic thread trimming sewing machine, 11 is a needle bar, 12 is a sewing machine needle, 13 is a cloth presser support rod, 14 is a cloth presser, and 1 is a presser foot.
Reference numerals 5 and 5 respectively denote the threading devices for the needle holes of the sewing machine. Sewing needle 12
As is well known, the upper end attachment portion (having a D-shaped cross section) is inserted into a vertical blind hole that opens to the lower end surface of the needle bar until its upper end abuts the blind hole upper end wall, and It is fixed with a fixing screw that is screwed to the needle bar,
As long as the needle hole is oriented in the left-right direction in FIG. 1 in the state of being fixed to the needle bar 11 and the sewing needle 12 is fixed to the needle bar 11 in a normal state, the sewing machine starts from the lower end surface of the needle bar 11. The distance L to the needle hole of the needle 12 is constant.

The threading device 15 for the sewing machine needle hole has a hook 16 which is inserted into and removed from the needle hole of the sewing machine needle 11 from the right side in FIG.
A guide 17 to which the hook 16 is fixed, a swing arm 18 that slidably supports the guide 17 in the vertical direction, and a spring 19 that biases the guide 17 upward with respect to the swing arm 18. The swing arm 18 is provided with a mounting bracket 21 in which an upper end thereof is rotatably supported by a horizontal shaft 20 in the front-rear direction.

The mounting bracket 21 has a portion 21a having a U-shaped planar shape and a mounting portion 21b extending upward from the upper end of the rear side of this portion 21a. It is fixed to the mounting portion 10a formed on the rear surface of the sewing machine arm 10 by two fixing screws 22.
The front and rear ends of the horizontal shaft 20 are rotatably supported by the rear side and the front side of the portion 21a.

The swing arm 18 has flange portions 18a and 18b for penetrating the horizontal shaft 20 between the rear side and the front side of the portion 21a of the mounting bracket 21 so as to be adjacent to the rear side and the front side. Have. The horizontal shaft 2 is provided between these flange portions 18a and 18b.
Horizontal shaft 2 by retaining rings 23A, 23B attached to 0
0 has been prevented from slipping out. Flange portions 18a, 18
The arcuate surface 18h8 of FIG. 8b is centered on the horizontal axis 20) and is provided with a recess 18c.
The convex portion 24a of the leaf spring 24 attached to is engaged with the concave portion 18c to hold the swing arm 18 in the horizontal standby position (see FIG. 8). Leaf spring 24
Is fixed to the upper outside of the left side of the portion 21a of the mounting bracket 21 with a screw, and extends inside the left side of the portion 21a via the lower side of the left side of the portion 21a.

The swing arm 18 is a mounting bracket 2
1 extends from the position of the portion 21a to the front and downward, and the front end portion (or the lower end portion) of the swing arm 18
18c is located adjacent to the right side of FIG. The guide 17 located on the left side of the front end portion 18c swings by slidably inserting the shaft portion of the screw 25 into a vertically long slot 18d formed in the front end portion 18c and screwing the shaft portion into the guide 17. The arm 18 is attached so as to be vertically movable. The lower end of the guide 17 is provided with a protrusion 17a slidably penetrating the notch 18e of the swing arm 18, and the tip of the protrusion 17a and the swing arm 18 are provided on the right side of the swing arm 18 in FIG. A spring 19 is stretched between the protrusion 18f and the protrusion 18f.
The vertical movement of the guide 17 with respect to the swing arm 18 is limited by the contact between the shaft portion of the screw 25 and the upper and lower ends of the elongated hole 18d. A knob 18g for rotating operation is provided on the front end of the mounting bracket 21.

The hook 16 fixed to the guide 17 is, as shown in FIGS. 5 to 7, a hook portion 16a which is positioned perpendicular to the side surface of the guide 17 and an L which is positioned parallel to the side surface of the guide 17. It consists of a character-shaped mounting part 16b,
It is riveted with the guide members 26 and 27 while being sandwiched between the pair of guide members 26 and 27. The guide members 26 and 27 include guide portions 26 a and 27 a that are positioned perpendicularly to the side surface of the guide 17, and L-shaped attachment portions 26 b and 27 b that are positioned parallel to the side surface of the guide 17. These hooks 16, guide members 26, 27
Is fixed to the guide 17 by two screws 28 which are screwed into the guide 17 through two vertically elongated holes (see FIG. 7) formed therein. With this fixing structure,
Hook 16, guide member 26, 27 for the guide 17
The fixed position of can be adjusted.

A forked body 17b extending leftward in FIG. 1 is formed at the upper end of the guide 17. The bifurcated body 17b, as shown in Figures 1-4, the upper sewing needle 12 and the distal end portion 17b ₁ was horizontally extending toward the guide 17 is bent downward, so as to sandwich the sewing needle 12 even natural The distance between the tip portions 17b ₁ is gradually increased toward the tip. Bifurcated body 1
The upper surface of 7b forms a vertical positioning portion 17c that can contact the lower end surface of the needle bar 11, and the opposing surface of the bifurcated body 17b forms a horizontal positioning portion 17d that can contact the peripheral surface of the sewing machine needle. When the swing arm 18 is located at the standby position, the guide 17 is displaced relative to the swing arm 18 slightly above the position shown in FIGS. 1 to 3, and the swing arm 18 is moved from the standby position to the position shown in FIGS. When it is rotated to the use position shown in FIG. 3, as shown in FIG. 8, the tip portion 17b ₁ of the bifurcated body 17b comes into contact with the lower end surface of the needle bar 11 to move the vertical positioning portion 17c to the lower end surface of the needle bar. And abut on the peripheral surface of the sewing machine needle 12 to guide the horizontal positioning portion 17d to abut on the peripheral surface of the sewing machine needle. The right end of the horizontal positioning portion 17d in FIG. 1 functions as a rotation stopper of the swing arm 18, that is, a use positioning stopper by contacting the sewing machine needle 12.

From the vertical positioning portion 17c to the hook 16
To the hook portion 16a is equal to the distance L from the lower end surface of the needle bar 11 to the needle hole of the sewing machine needle 12, and the horizontal positioning portion 17d and the hook portion 16a of the hook 16 occupy the same position in the front-rear direction. Therefore, even if the upper stop position of the sewing machine needle 12 varies when the sewing machine is stopped, and regardless of the variation in the relative position of the component parts attached to the sewing machine arm due to the dimensional accuracy and assembly accuracy of the component parts, By simply rotating the swing arm 18 from the standby position to the use position, the hook portion 16a of the hook 16 can be smoothly and surely aligned with the needle hole position.

A torsion coil spring 29, which is a thread hooking elastic member, is attached to a mounting portion 18j provided on the upper side of the front end portion of the swing arm 18 so that the torsion coil spring 29, which is an elastic member, extends horizontally in the front-rear direction above the hook 16. Installed by. This torsion coil spring 29 has a rear end as a thread hooking portion 29a, and at the time of threading, the tip end side portion of the thread hooked on the hook 16 (the portion between the hook and the tip held by the finger) or the balance. The portion between the hole and the hook is hooked on the thread hooking portion 29a.

Next, threading through the sewing machine needle hole using the sewing machine needle hole threading device 15 will be described. During the sewing operation, the swing arm 18 is pivotally operated to a horizontal standby position indicated by a chain double-dashed line in FIG. 8, and the recess 18c of the swing arm 18 and the protrusion 24a of the leaf spring 24 are engaged with each other to swing the swing arm. 18 is held in the standby position.

When the sewing machine is stopped, the needle bar 11 and the sewing needle 12 fixed to the needle bar 11 are in the upper stop position. In order to thread the needle hole of the sewing machine needle 12, the swing arm 18 in the standby position is pivotally operated to the use position shown in FIGS. Although there are some variations in the upper stop positions of the needle bar 11 and the sewing machine needle 12, when the swing arm 18 rotates from the standby position to the use position, the tip 17b ₁ of the bifurcated body 17b of the guide 17 is fixed to the needle bar 11. To contact the lower end surface of the sewing machine needle 12 to contact the lower end surface of the needle bar, and to contact the peripheral surface of the sewing machine needle 12 to guide the horizontal positioning portion 17d to contact the peripheral surface of the sewing machine needle. . At that time, the guide 17 always moves downward with respect to the swing arm 18. Vertical positioning portion 17c and needle bar 1
The height and front-back direction position of the hook portion 16a of the hook 16 fixed to the guide 17 by contact with the lower end surface of No. 1 and contact between the horizontal positioning portion 17d and the sewing machine needle peripheral surface are the lower end surface of the needle bar 11. And the peripheral surface of the sewing machine needle 12 is automatically determined as a reference. Horizontal positioning part 17d
And the hook portion 16a of the hook 16 are located at the same position in the front-rear direction, and the hook 16
Since the distance to the hook portion 16a of the hook is equal to the distance L from the lower end surface of the needle bar 11 to the needle hole of the sewing machine needle 12, the hook 1
The height of the hook portion 16a of No. 6 corresponds to the height of the needle hole of the sewing machine needle 12, so that when the swing arm 18 is in the use position, the hook portion 16a moves the needle hole of the sewing machine needle 12 from the right side to the left side in FIG. Penetrate. In this way, the hook 16
When "a" penetrates the needle hole of the sewing machine needle 12 from the right side to the left side in FIG. Make an accurate entry into.

A thread (not shown) guided downward through the hole of the balance in the state of FIGS. 1 to 3 is passed through the hole of the needle bar 11 and below the hook 16 as shown in FIGS. The thread hooking portion 29 of the torsion coil spring 29 is hooked on the portion 16a and the tip end side portion of the thread is set to an appropriate length.
hook on a. Alternatively, the thread (not shown) guided downward through the hole of the balance is first used for the torsion coil spring
It is hooked on the thread hooking portion 29a of No. 9 and then passed under the hook 16 and hooked on the hook portion 16a. After this,
As shown in FIG. 1, by swinging the swing arm 18 from the use position to the standby position, the hook portion 16a
Pulls out from the needle hole of the sewing machine needle 12 while hooking the thread, and the thread passes from the left side to the right side of the needle hole. At that time, due to elastic deformation of the torsion coil spring 29, the thread hooking portion 29
When a is displaced from the state of the two-dot chain line to the state of the solid line, the tip end side portion of the yarn (the portion between the balance and the hook is moved to the yarn hooking portion 2
When it is hooked on 9a, the portion between the balance and the hook) is delivered with a proper tension applied.

[0026]

As described above, in the threading device for a sewing machine needle hole according to the invention of this application, when the swing arm is rotated from the standby position to the use position, the upper and lower sides of the guide to which the hook is fixed are moved up and down. The direction positioning portion engages with the lower end surface of the needle bar to position the height of the hook uniformly with respect to the lower end surface of the needle bar, and the horizontal positioning portion of the swing arm contacts the peripheral surface of the sewing machine needle. Align the horizontal position of the hook with the sewing machine needle. Since the height of the needle hole of the sewing machine needle is constant with respect to the lower end surface of the needle bar, the height of the hook exactly matches the height of the needle hole. Further, since the horizontal position of the needle hole of the sewing machine needle is constant with respect to the sewing machine needle, the horizontal position of the hook exactly matches the horizontal position of the needle hole. Therefore, even if the height of the needle hole when the sewing machine is stopped varies to some extent, the hook can be accurately inserted into the needle hole simply by rotating the swing arm from the standby position to the use position. Thereafter, as in the conventional device, the thread is hooked on the hook protruding from the needle hole, and the swing arm is rotated from the use position to the standby position to pass the thread through the needle hole. Therefore, the operation of adjusting the height of the needle hole unlike the conventional device is unnecessary, and the work efficiency can be improved.

Further, in the guide, the thread hooking elasticity for feeding the thread hooked on the hook passed through the needle hole into the needle hole while applying a predetermined tension to the thread in the process of pulling out the thread together with the hook from the needle hole. By providing the member, when hooking the thread on the hook protruding from the needle hole and rotating the swing arm from the use position to the standby position,
By simply grasping the tip of the thread with a finger, the thread can be fed while giving an appropriate thread tension in response to the thread being pulled into the needle hole by the hook, making the threading action easier. You can

Further, the vertical positioning portion and the horizontal positioning portion extend horizontally from the upper end of the guide toward the sewing machine needle with the swing arm in the use position, and the tip portion. Is a bifurcated body formed by bending the sewing machine downward so as to sandwich the sewing machine needle, and the tip portion of the bifurcated body is formed by the bifurcated body in which the interval between the tip portions is gradually increased toward the tip. Since it acts as a guide when abutting against the rod and the sewing machine needle, the hooks will not be affected regardless of variations in relative positions of the components mounted on the sewing machine arm due to dimensional accuracy and assembly accuracy of the components. The positions of the needle holes can be smoothly and surely matched.

Further, the horizontal shaft is supported by a mounting bracket which is attachable to and detachable from the sewing machine arm, and the swing arm is formed with an arc surface centered on the horizontal shaft and a recessed portion located on the arc surface. Then, a leaf spring having a free end formed with a convex portion that comes into pressure contact with the circular arc surface is fixed to the mounting bracket, and the concave portion and the convex portion are engaged and held at the standby position of the swing arm. By doing so, the sewing machine can be purchased and installed in the sewing machine at a necessary time after the purchase.

[Brief description of drawings]

FIG. 1 is a front view showing a state in which an embodiment of the invention of this application is attached to a sewing machine.

FIG. 2 is a view seen from the left side of FIG.

FIG. 3 is a diagram viewed from the right in FIG.

4 is a cross-sectional view taken along the line AA in FIG.

5 is a front view of the hook assembly in FIG. 1. FIG.

FIG. 6 is a left side view of the hook assembly in FIG.

FIG. 7 is a plan view of the hook assembly in FIG.

FIG. 8 is a view for explaining the operation of one embodiment of the invention of this application.

FIG. 9 is a diagram for explaining the operation of one embodiment of the invention of this application.

FIG. 10 is a diagram for explaining the operation of one embodiment of the invention of this application.

FIG. 11 is a diagram for explaining the operation of one embodiment of the invention of this application.

[Explanation of symbols]

10 ... Sewing machine arm 11 ... Needle bar 12 ... Sewing needle 15 ... Sewing machine needle threading device 16 ... Hook 16a ... Hook part 17 ... Guide 17b ... Bifurcated part 17c ... Vertical positioning portion 17d ... Horizontal positioning portion 17b ₁ ... Bifurcated tip 18 ... Swing arm 18c ... Swing arm recess 18h ... Swing arm arc surface 19・ ・ ・ Spring 20 ・ ・ ・ Horizontal shaft 21 ・ ・ ・ Mounting bracket 24 ・ ・ ・ Leaf spring 24a ・ ・ ・ Leaf spring convex portion 29 ・ ・ ・ Torsion coil spring (thread hook elastic member) 29a ・ ・ ・ Torsion Threading part of coil spring

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 58-138483 (JP, A) JP 3-133485 (JP, A) JP 2-104391 (JP, A) JP 61- 18479 (JP, B2) JP-B 56-36958 (JP, B2) JP-B 33-8443 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) D05B 87/00-87 / 02

Claims (4)

(57) [Claims] 1. A hook, which is taken in and out from one side of a needle hole of a sewing machine needle fixed to a needle bar, is fixed to a guide, and this guide is supported by a swing arm so as to be vertically movable, and this swing arm is supported on the sewing machine arm. On the other hand, an urging member for urging the guide upward is provided so that it can be reciprocally rotated between a use position and a standby position about a horizontal axis in the front-rear direction. A threading device for a sewing machine needle hole, which is provided with an up-down direction positioning part capable of contacting an end surface and a horizontal positioning part capable of contacting a peripheral surface of the sewing machine needle. 2. The threading device for a sewing machine needle hole according to claim 1, wherein a predetermined tension is applied to the thread due to elasticity in the process of pulling out the thread hooked on the hook passing through the needle hole from the guide hole together with the hook. A threading device for a needle hole of a sewing machine, characterized in that a thread hooking elastic member is provided for feeding the thread into the needle hole. 3. The threading device for a sewing machine needle hole according to claim 1, wherein the vertical positioning portion and the horizontal positioning portion of the guide of the guide are in a state where the swing arm is in a use position. A bifurcated body that extends horizontally from the upper end toward the sewing machine needle and bends the tip portion downward so as to sandwich the sewing machine needle, and gradually increases the distance between the tip portions as it approaches the tip. A threading device for a needle hole of a sewing machine, which is formed by a forked body. 4. The threading device for a sewing machine needle hole according to claim 1, wherein the horizontal shaft is supported by a mounting bracket that is removable from the sewing machine arm.
The swing arm has a circular arc surface centered on the horizontal axis and a concave portion located on the circular arc surface, and a leaf spring having a convex portion formed at its free end for press-contacting the circular arc surface is attached to the mounting bracket. The threading device for a sewing machine needle hole, characterized in that the concave portion and the convex portion are engaged with each other and held in position at the standby position of the swing arm.