JPH08280977A - Threading device in sewing machine - Google Patents

Abstract

PURPOSE: To perform easily, accurately and safely threading work by facing a thread hooking nail for threading to a sewing needle of a sewing machine and penetrating the mail into a thread hole when the sewing needle of the sewing machine is positioned at the upper dead point by performing a simple operation which lowers a plate-like member by a threading means. CONSTITUTION: When a threading lever 22 for a single needle is pushed down and rotated, a threading safety plate 16 is pulled downward. At this time, when a sewing needle 10 of a sewing machine is located in the neighborhood of the upper dead point, the threading safety plate 16 is pushed by a needle clamp body driving pin 15 and is rotatably moved to the back of the sewing machine. In addition, the threading safety plate 16 is lowered by the position where it is brought into contact with a needle fixing hooking stage 17. During this, a needle fixing hook is hooked to the needle clamp body driving pin 15 to stop lowering of a needle clamp body driving arm 14 to prevent the sewing needle 10 of the sewing machine from lowering during threading work. In addition, a threading set 20 is rotatably moved from a storing position behind the sewing machine and a thread hooking nail 18 for threading is penetrated from the back of the sewing needle of the sewing machine. Then, the thread hooking nail 18 for threading hooks the needle thread and it is released from the thread hole of the sewing needle of the sewing machine and retreated therefrom.

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 to a threading device for a sewing machine incorporated in a sewing machine main body.

[0002]

2. Description of the Related Art Threading a thread through a thread hole of a sewing needle of a sewing machine is a difficult task even for an operator with good eyesight. Therefore, various threading devices have been proposed. Conventionally, as such a threading device, a threading claw for threading, which is fixed to the lower end of a threading shaft that moves up and down in parallel with a sewing machine needle, is lowered by an operating body to a position that coincides with the thread hole of the sewing machine needle. After the threading claw for threading descends to a predetermined position, the threading shaft is further rotated by the operating body to insert the threading claw for threading into the thread hole of the sewing machine sewing needle,
Hook or thread the thread on the threading claw for threading,
After that, a device for threading by retracting the threading claw for threading (Japanese Patent Publication No. 34-10979, Japanese Utility Model Publication No. 61-35188, Japanese Patent Application Laid-Open No. 4-64386, and Japanese Patent Application Laid-Open No. 4-89095). ), The operating arm that operates for threading is pivotally attached to a proper position of the needle bar support, and the pivotal attachment portion of the operating arm is formed by an arcuate surface having an elongated hole, and is fixed to the operating arm. A device for threading by threading a threading piece provided at the end of the operating arm into the thread hole of the sewing machine needle to rotate the machine vertically (horizontally and horizontally).
No. 061), and the lower part of the head of the zigzag sewing machine or the presser bar, and by pressing the lever with a button from the front of the sewing machine, the small needle of the lever with a small needle is inserted into the thread hole of the sewing needle that is stationary at top dead center. An apparatus (Japanese Patent Application Laid-Open No. 3-158186) for penetrating and threading is proposed.

However, such a threading device was developed for an ordinary single-needle household sewing machine, and was not suitable for an overlock sewing machine equipped with a looper, a cloth cutting knife, and the like. Also, since the threading device must be installed on the threading shaft or the like having a threading claw for threading,
It was not suitable for a two-needle sewing machine with limited space. Therefore, the threading work in the two-needle sewing machine is
The complicated work with the fingertips was inevitable, which hindered improvement of the sewing work ability.

On the other hand, as a threading device which can be applied to an overlock sewing machine, a threading member fixed to a rotary shaft provided to intersect with the cloth feeding direction is fixed to a knob fixed to the other end of the rotary shaft. Is operated to rotate so that the thread hooking needle of the threading member penetrates the hole of the needle, the thread is hooked on the thread hooking needle of this threading member, and then the thread hooking needle of the threading member is retracted. An apparatus (Japanese Patent Application Laid-Open No. 2-104391) for threading by doing so has been proposed. However, in such a threading device, the rotating shaft has to be provided in a gap of another power transmission mechanism or the like, which may complicate the mechanism.

Further, as a threading device applicable to a sewing machine having a plurality of needles such as a two-needle sewing machine, it is pivotally attached to a shaft portion of a needle stop portion of a needle bar and has a hook for protecting a guide which can be moved back and forth. Section, the left and right movable main body provided with the thread guide section is pivotally supported by the limited bending section so as to limit the movement range,
A threading device (Japanese Patent Publication No. Sho 39-1782) for threading by allowing two needles to go in and out, and a rotary shaft intersecting with the cloth feeding direction in a gap of another power transmission mechanism or the like. A device for performing threading by mounting a threading member whose swinging surface is switchable with respect to the rotary shaft and causing the threading member to face either one of the two needles by this switching operation (special feature Kaihei 3-133483) is proposed.

However, the threading device pivotally attached to the needle stop portion of the needle bar is configured to be detachably attached to the cylindrical thread portion of the needle stop body at the lower portion of the needle bar, and is a two-needle overlock sewing machine. As described above, it cannot be used in an overlock sewing machine having a different needle bar configuration and having a looper and a knife for cutting cloth. Further, in the device for threading, which can change the threading position by the switching operation, the mechanism may be complicated.

Further, as a threading device which can be applied to a sewing machine having a plurality of needles such as a two-needle sewing machine, the threading mechanism is moved in the horizontal direction by the moving means, and the thread hook is provided with two sewing needles. One of the sewing needles is opposed to the other, and then the thread hook is moved in parallel in the vertical direction by the aligning means so that the thread hook is positioned on the same straight line as the needle hole of the opposed needle. A threading device (Japanese Patent Laid-Open No. 3-251292) for threading a threading hook into a needle hole of a sewing needle and a drive shaft having a drive cam are rotated to rotate the threading installation base. The threading member provided in the threading mechanism is moved up and down and pivoted to be positioned at a predetermined sewing needle position, and the threading claw for threading is aligned with the thread hole of the sewing needle by the operating lever. The threading claw for threading down to a predetermined position, and then further rotating the threading shaft with the operating lever to insert the threading claw for threading into the thread hole of the sewing machine needle. There has been proposed a threading device (Japanese Patent Laid-Open No. 5-317563) that hooks a thread on the thread and then retracts the threading claw for threading to perform threading.

However, the threading device provided with the moving means and the positioning means is not suitable for a multi-needle sewing machine in which the space for installing the threading device is limited because each means is provided independently. It was Further, in the threading device having the drive shaft having the drive cam, the threading member must be moved up and down and pivoted in order to make the operation one stroke, so that the drive cam has a complicated structure. Moreover, the number of parts was large.

Generally, a sewing product is placed on the left side of the sewing machine needle as viewed from the front of the sewing machine and sewn. Since the cloth is fed by the right hand and the sewing operation is performed by the left hand, a space for operation is provided on the left side of the sewing machine main body. However, in some types of threading devices (JP-A-4-89095, JP-A-3-251292, and JP-A-5-317563), they are installed on the left side of the sewing needle. Was there.

Further, most threading devices are sewing needles,
It is inexpensive because it does not have a safety mechanism that prevents damage to the threading claws for threading or the operation of the sewing machine during threading work, and the threading device that has a safety mechanism also has a complicated mechanism. There was a problem that it was not possible to provide a large sewing machine.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and allows a thread to be threaded through a thread hole of a sewing machine needle with a simple operation, and an accident due to an erroneous operation can be reliably performed. An object of the present invention is to provide a threading device for a sewing machine which can be prevented and which has a simple mechanism and is compact.

[0012]

A threading device for a sewing machine according to the present invention which achieves such an object is provided in a sewing machine main body having a needle retaining drive means for reciprocally driving a needle retainer to which a sewing needle is fixed. In a threading device of a sewing machine in which a threading claw for threading is made to face a sewing needle and penetrates into a thread hole of the sewing needle, the needle anchor driving means is connected to the needle anchor and protrudes from the needle anchor driving means. A needle retaining drive pin, a first end face cam part that engages with the needle retainer drive pin when the sewing machine needle is substantially located at the top dead center, and a second end face cam part that interlocks with the first end face cam part. A hook member on which the formed plate-like member and the second end-face cam portion of the plate-like member slides only when the first end-face cam portion of the plate-like member fixed to the sewing machine body engages the needle retention drive pin. And the thread hook for threading, which is pivotally attached to the plate member, as a sewing needle. And a threading means for direction, the second end surface cam portion of the plate-like member in which the hook hunt notch in the hook member is formed when the sewing machine needle is positioned in other than the top dead center substantially.

Further, the threading device of the sewing machine of the present invention is provided with a needle fixing member which is engaged with the plate-like member and restricts the lowering of the sewing machine needle only when the sewing machine needle is substantially located at the top dead center. It is a thing. Further, in the threading device of the sewing machine of the present invention, the threading means includes a threading set having a threading claw for threading, a threading arm to which the threading set is fixed, and a plate engaged with the threading arm. The threading lever is pivotally mounted on the member, and the needle threading member and the threading lever are attached to the body of the sewing machine. Further, in the threading device of the sewing machine of the present invention, a tension spring for constantly urging the plate member in the hook member direction is provided between the hook member and the plate member. In the sewing machine threading device of the present invention, the threading means is provided with a switching means for positioning the threading claw for threading on any one of the plurality of sewing needles.

[0014]

When the plate-like member is lowered by the threading means when the sewing machine sewing needle is substantially located at the top dead center, the connecting pin projecting from the needle retaining drive means is provided with the first member formed on the plate-like member. One end face cam portion is engaged. Further, when the plate-shaped member is lowered, the plate-shaped member is rotated rearward of the sewing machine by pressing the first end surface cam portion by the connecting pin. At this time, the second end-face cam portion formed on the plate member slides along the hook member. Therefore, the plate member is lowered by the threading means without being restricted, so that the threading claw for threading can be made to face the sewing machine needle and penetrate into the thread hole of the sewing machine needle. After threading the thread on the threaded threading claw that has penetrated, when the plate member is raised by the threading means, the threading threading claw retracts to the rear of the sewing machine sewing needle to move from the thread hole of the sewing machine sewing needle. The thread that has escaped and is hooked on the threading claw for threading is passed through the thread hole of the sewing needle.

On the other hand, when the plate-like member is lowered by the threading means when the sewing machine sewing needle is located substantially at a position other than the top dead center, the first end surface cam portion formed on the plate-like member retains the needle. Since it does not engage with the connecting pin projecting from the drive means, the first end cam portion is not pushed by the connecting pin, and the plate-like member descends without rotating. Therefore the second
Since the notch formed in the end face cam portion is hooked on the hook member, the plate member is restricted from moving downward. Therefore, the threading means does not operate, and the threading claw for threading does not face the sewing needle.

Further, by engaging the plate fixing member with the needle fixing member that restricts the lowering of the sewing machine sewing needle only when the sewing machine sewing needle is located at the top dead center, the needle drive arm is fixed and threading work is performed. The operation of the sewing machine can be prevented. Also,
The threading means can rotate the threading arm pivotally attached to the mounting member and fixed to the threading set only by pressing the threading lever.

Further, by providing a tension spring for constantly urging the plate member in the direction of the hook member between the hook member and the plate member, after the thread is threaded through the thread hole of the sewing machine sewing needle, the thread threading claw for threading the thread. Can be automatically returned to its original position. Further, by providing the threading means with a switching means for positioning the threading claw for threading on any of a plurality of sewing needles of the sewing machine, it is possible to correspond to a sewing machine having a plurality of needles.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a threading device for a sewing machine according to the present invention will be described below with reference to the drawings. The threading device for a sewing machine of the present invention can be applied to a one-needle, three-thread overlock sewing machine 1 as shown in FIG. 3, and this overlock sewing machine 1 is provided from one spool 60A through a thread guide 3. One needle thread 51A that is fed out, and two thread windings 60B,
Two looper threads 51B and 51C fed out from 60C
And these three sewing threads 51A, 51B, 51C are used.
A thread tension device 4 is provided inside the overlock sewing machine 1 corresponding to the above. Further, the overlock sewing machine 1 is provided with thread guides 5 and 11 for guiding the needle thread 51A from the thread tension device 4 for the sewing needle to the sewing machine sewing needle 10 fixed to the needle stay 9. As shown in FIG. 1, the needle stay 9 is connected to a needle stay link 12 by a connecting pin 13, and the needle stay link 12 is a needle stay drive means that is driven up and down by rotation of a main shaft (not shown) as a needle stay drive arm. It is connected to 14 by a needle retaining drive pin 15. The needle anchor drive pin 15 is provided on the left side of the sewing machine when viewed from the front.

In such an overlock sewing machine 1, as shown in FIGS. 1 and 2, the threading device of the sewing machine serves as a plate-like member which can be engaged mainly with the needle anchor drive pin 15 provided in a protruding manner. A threading safety plate 16, a needle fixing hook base 17 as a hook member that is fixed to the sewing machine main body 6 and is engaged with the threading safety plate 16, and a threading claw 18 that is pivotally attached to the threading safety plate 16. Sewing needle 10
And a threading means 19 which is opposed to.

The threading safety plate 16 has a first end cam portion 16a which engages with the needle anchor drive pin 15, and the needle fixing hook base 1.
A second end face cam portion 16b having a notch 16c that is hooked to the notch 17a formed in No. 7 is formed. The second end cam portion 16b of the threading safety plate 16 is fitted into the notch 17a of the needle fixing hook base 17. The threading means 19 is engaged with the threading set 20 having the threading claw 18 for threading, the threading arm 21 for one needle to which the threading set 20 is fixed, and the threading arm 21 for this one needle. Threading lever 22 for one needle pivotally attached to the threading safety plate 16 and the sewing machine main body 6
And a threading mount 23 as a mounting member to which a single-needle threading arm 21 and a single-needle threading lever 22 are pivotally attached.

The threading arm 21 for a single needle is a threading mount 23.
It is rotatably attached by a screw 26 via a spacer 24 and a wave washer 25 loosely fitted to the spacer 24 at one end thereof. As a result, the single-thread threading arm 21 can be smoothly rotated by the elastic force of the wave washer 25 without play. The threading lever 22 for single needle has an L-shaped arm 2
2a, an arm portion 22b having a bow-shaped tip portion, and a mounting portion 22c having a mounting hole. L-shaped arm 22
A connecting arm 22d is provided in the center of a, and the connecting arm 2d
2d is a spacer 29 on the lower end 16d of the threading safety plate 16.
It is rotatably attached by a screw 30 via. Further, a bow-shaped elongated hole 22e is formed in the arm portion 22b, and the arm portion 21a formed on the threading arm 21 for a single needle is inserted into the bow-shaped elongated hole 22e. The mounting portion 22c is rotatably attached to the other end of the threading mounting base 23 with a screw 32 via a spacer 31. The L-shaped arm 22a
A threading lever cap 33 as a finger hook is fixed to the tip of the to facilitate the threading operation.

The threading mount 23 is fixed to a presser bar mounting plate 27 fixed to the sewing machine body 6. The presser bar attachment plate 27 is for attaching the presser bar 8 to which the cloth presser 7 is fixed to the sewing machine main body 6. Specifically, presser bar mounting plate 2
The convex portion 23a formed on the threading mount 23 is engaged with the hole 27a formed in the hole 7, and the screw 28 is pressed down.
7 through which the threading mount 23
It is fixed by being screwed into the screw hole 23b.

As a safety mechanism, the threading device thus constructed has a needle fixing hook 34 as a needle fixing member for restricting the lowering of the sewing needle 10 when the sewing needle 10 is substantially located at the top dead center. Is provided. The needle fixing hook 34 is rotatably attached to the arm portion 17b formed on the needle fixing hook base 17 with a screw 36 via a spacer 35. Further, the needle fixing hook 34 has an arcuate long hole 34a.
Is formed, and the threading safety plate 16 is inserted into the arcuate elongated hole 34a.
The convex portion 16e formed in is inserted. Further, a lower end hook portion 34b is formed on the needle fixing hook 34, and when the threading safety plate 16 is lowered by the threading operation, the needle fixing hook 34 rotates counterclockwise about the spacer 35 as a spindle. Thereafter, the needle fixing hook 34 is locked by the needle retaining drive pin 15 protruding from the needle retaining drive arm 14.

Further, the spring hooking hole 1 of the needle fixing hook base 17
7c and the threading lever spring 37 as a tension spring is hooked between the threading safety plate 16 and the spring hooking hole 16g of the arm 16f formed in the threading safety plate 16 to urge the threading safety plate 16 upward. At the same time, bias the front side of the sewing machine,
Since the bottom of the notch 16c of the threading safety plate 16 and the end of the notch 17a of the needle fixing hook stand 17 can be reliably brought into contact with each other, the single needle engaged with the single-needle threading lever 22 The threading arm 21 can be kept in the storage position at all times.

When the single-needle threading lever 22 is pressed and rotated in such a configuration, the threading safety plate 16 is pulled downward. At this time, when the sewing needle 10 is near the top dead center, as shown in FIG. 4, the inclined surface of the first end cam portion 16a of the threading safety plate 16 abuts on the needle anchor drive pin 15, and after the abutment. When the threading lever 22 for the single needle is further depressed, the threading safety plate 16 is moved to the needle anchor drive pin 1
It is pushed by 5 and rotationally moves to the rear of the sewing machine along the inclined surface of the first end surface cam portion 16a until it reaches the cam top.

When the threading safety plate 16 is rotated downward while being pulled downward, the bottom portion of the notch 16c of the threading safety plate 16 which is in contact with the end of the notch 17a of the needle fixing hook base 17 is also in contact. And the second end cam portion 1 of the threading safety plate 16 is further attached to the end of the notch 17a of the needle fixing hook base 17.
The notch 16c of 6b is not caught, and the inclined surface of the second end surface cam portion 16b of the threading safety plate 16 is fixed to the needle fixing hook base 17
Slide the end of the notch 17a. Therefore, as shown in FIG. 5, the threading safety plate 16 is lowered until the stopper portion 16h comes into contact with the end of the notch 17a of the needle fixing hook base 17.

During this time, the needle fixing hook 34 is rotated by the lowering of the convex portion 16e of the threading safety plate 16 inserted in the elongated hole 34a, so that the lower end hook portion 3 of the needle fixing hook 34 is rotated.
4b engages with the needle drive pin 15 (FIGS. 6 and 7). As a result, the downward movement of the needle retaining drive arm 14 can be stopped, so that it is possible to prevent the sewing machine sewing needle 10 from falling during the threading operation.

When the threading lever 22 for the single needle is depressed by the threading operation, the threading lever 22 for the single needle is separated from the operations of the threading safety plate 16 and the needle fixing hook 34 described above. The arm portion 21a of the single-needle threading arm 21 inserted into the arcuate elongated hole 22e of the arm portion 22b is pushed down (FIGS. 6, 7, and 8). As a result, the single-needle threading arm 21 rotates about the spacer 24 as a support shaft, so that the threading set 20 fixed to the single-needle threading arm 21 rotates and moves from the storage position behind the sewing machine to perform threading. The thread hooking claw 18 for threading fixed to the set 20 penetrates from the back of the sewing needle.

Here, the needle thread 51A, which has already been threaded according to the thread path sequence, is pulled by pulling the thread threading claw 18 of the thread threading set 20 so that it is pulled from the thread threading lever 22 for one needle. Release. By releasing the hand from the threading lever 22 for the single needle, the threading lever 22 for the single needle is returned by the urging force of the threading lever spring 37 via the threading safety plate 16, and the threading set 20 is rotated. While retracting to the back of the sewing machine needle 10. At the same time, thread hook 1 for threading
In the state where the hook-shaped tip of the needle thread 51A is hooked, the needle thread 8 escapes from the thread hole 10a of the sewing machine sewing needle 10 and retracts. And
The threading operation is completed by pulling the loop-shaped sewing thread through the thread hole 10a of the sewing needle 10 and pulling out the tip thereof.

On the other hand, when the sewing machine needle 10 is substantially located at a position other than the top dead center, as shown in FIGS. 9 and 10,
When the single-needle threading lever 22 is depressed, the inclined surface of the first end surface cam portion 16a of the threading safety plate 16 does not come into contact with the needle anchor drive pin 15, so the threading safety plate 16 rotates rearward of the sewing machine. It is pulled downward without moving. Threading safety plate 16
If the bottom of the notch 16c of the threading safety plate 16 does not separate and is caught at the end of the notch 17a of the needle fixing hook base 17 when the needle is pulled downward without rotating behind the sewing machine, it is more than 1
It becomes impossible to push down the threading lever 22 for the main needle. As a result, the single-needle threading arm 21 cannot rotate, and therefore the sewing machine sewing needle 10 and the threading thread hooking claw 1 are erroneously operated.
8 can be prevented from being damaged.

Although the present invention is applied to the single-needle, three-thread overlock sewing machine 1 in the present embodiment, the present invention is not limited to this and may be applied to a two-needle, four-thread overlock sewing machine.
The threading device applied to the two-needle four-thread overlock sewing machine can be used only by replacing the threading means 19 of the threading device applied to the one-needle three-thread overlock sewing machine 1.

The threading means used in such a two-needle, four-thread overlock sewing machine is a threading mount 23 and a threading claw for threading applied to the one-needle, three-thread overlock sewing machine 1. A threading set 20 having 18, a switching means 41 (FIG. 11) for positioning the threading claw 18 for threading at a predetermined sewing needle position, and two needles pivotally attached to one end of the threading mount 23. The threading lever 42 (FIG. 11) is provided.

The switching means 41 includes a threading arm base 43 pivotally attached to one end of the threading mount 23, a two-needle threading arm 44 to which the threading set 20 is fixed, and a two-needle threading. Arm 44
Threading claw 18 for threading of threading set 20 fixed to
And a threading switching lever 45 for moving the sewing machine to a predetermined position of the thread hole of the sewing needle. The threading armrest 43 is bent in an L shape, and a hole 43a and a relief hole 43b are formed in one of the bent plate surfaces to form a convex portion 43c.
Further, the two-needle threading arm 44 is provided with a long hole 44a and a guide groove 44b, and a convex portion 44c is formed. Further, the threading switching lever 45 is provided with a screw hole 45a and a drive cam hole 45b, and a spring hook 45c is formed.
The two-needle threading arm 44 and the threading switching lever 45 are overlapped with each other, centering on the bent one plate surface of the threading arm base 43, and the threading switching lever 45 has two screw holes 45a. A screw 47 is screwed through a long hole 44a of the needle threading arm 44 and a spacer 46 inserted into the hole 43a of the threading arm base 43 so that the screw 47 is rotatably combined. At this time, the convex portion 43c of the threading arm base 43 is formed on the threading arm 4 for two needles.
4, the convex portion 44c of the two-needle threading arm 44 penetrates the escape hole 43b of the threading arm base 43 and is inserted into the drive cam hole 45b of the threading switching lever 45.

The other bent plate surface of the threading arm rest 43 is attached to one end of the threading mount 23 through a spacer 24 and a wave washer 25 loosely fitted in the spacer 24, and the screw 2
It is rotatably attached at 6. As a result, the needle threader arm 43 can be smoothly rotated by the elastic force of the wave washer 25 without play. In addition, the threading arm stand 4
The threading switching lever spring 48 is hooked between the spring hooking hole 43e formed in the other plate surface of No. 3 and the spring hooking 45c of the threading switching lever 45 to rotate the threading switching lever 45 in both directions. Threading arm 4 for 2 needles on either side
Always activate 4.

The two-needle threading lever 42 has substantially the same shape as the one-needle threading lever 22 and has an L-shaped arm portion 42a.
And an arm portion 42b having an arcuate tip and a mounting portion 42c having a mounting hole. The L-shaped arm portion 42a is provided with a connecting arm 42d slightly rearward from the tip, and the connecting arm 42d is rotatably attached to the lower end portion 16d of the threading safety plate 16 via a spacer 29 with a screw 30. Has been done. Further, a bow-shaped long hole 42e is bored in the arm portion 42b, and an arm portion 43d formed on the threading arm base 43 is inserted into the bow-shaped long hole 42e. The mounting hole 42c is rotatably attached to the other end of the threading mount 23 via a spacer 31 with a screw 32. The L-shaped arm 42
A threading lever cap 33 as a finger hook is fixed to the tip of a to facilitate the threading operation.

In this two-needle, four-thread overlock sewing machine, in order to fix the threading mount 23 to the presser bar mount plate 27 fixed to the sewing machine main body 6, the presser bar mount plate 27 is used.
The convex portion 23a formed on the threading mount 23 is engaged with the hole 27b formed in the hole 27b, and the screw 28 is inserted into the long hole 27c formed in the presser bar mounting plate 27 to insert the threading mount 23. It is fixed by screwing it into the screw hole 23b (Fig. 2). At this time, the mounting position of the threading mount 23 is adjusted so that a pressing device such as the cloth presser 7 can be exchanged when the threading set 20 fixed to the two-needle threading arm 44 is rotated. To do. Since the threading hole of the sewing machine needle is mounted in a direction orthogonal to the sewing machine drive shaft, the threading set 20 is adjusted to 10 degrees or less with respect to the direction perpendicular to the sewing machine drive shaft. It is desirable to adjust so as to tilt and intersect with each other to rotate.

In the switching means 41 of the threading means 40 thus configured, when the threading switching lever 45 is rotated, the switching operation as shown in FIG. 12 is performed. In FIG. 12, a thick broken line (threading switch lever 4
5) The thick one-dot chain line (thread threading arm base 43) and the thick two-dot chain line (thread threading arm 44 for two needles) are aligned with the thread hole 10 "a of the sewing machine sewing needle 10" used as the left needle. Shows the operating position of each part, and is represented by a thin broken line (threading switch lever 45).
The thin chain double-dashed line (two-needle threading arm 44) represents the operating position of each part when the thread needle arm 10'a of the sewing machine sewing needle 10 'used as the right needle is matched.

For the switching operation by the switching means 41, for example, when the operating arm 45d of the threading switching lever 45 is rotated to the right, the drive cam hole 45b of the threading switching lever 45 is provided with the convex portion of the threading arm 44 for two needles. 44c is moved toward the center of the spacer 46, and the two-needle threading arm 44 is moved to the lower right so that the threading set 20 is aligned with the thread hole 10'a of the sewing needle 10 '. When the operation arm 45d of the threading switching lever 45 is rotated to the left, for example, the drive cam hole 45b of the threading switching lever 45 moves the convex portion 44c of the two-needle threading arm 44 in the centrifugal direction of the spacer 46. Then, the two-needle threading arm 44 is moved to the upper left so that the threading set 20 is aligned with the thread hole 10 "a of the sewing needle 10".

As described above, the threading switching lever 45 of the switching means 41 allows the sewing machine needle 1 to be used as the right needle.
After selecting either 0'or the sewing needle 10 "used as the left needle and rotating it by pressing the threading lever 42 for the two needles, the above-described one-needle, three-thread overlock sewing machine 1 Similarly, the threading claw 18 for threading fixed to the threading set 20 can be guided to a thread hole of a predetermined sewing needle.

That is, when the sewing machine sewing needles 10 'and 10 "are substantially located at the top dead center, as shown in FIGS. 13, 14 and 15, the threading safety plate 16 cams the two needles. Threading set 2 fixed to the threading arm 44
0 is rotationally moved from the storage position at the back of the sewing machine, and the threading claw 18 for threading fixed to the threading set 20 is inserted from behind the sewing needle selected in advance. Further, when the sewing machine sewing needles 10 ', 10 "are substantially located other than the top dead center, as shown in FIG. 16, when the two-needle threading lever 42 is depressed, the first threading safety plate 16 is pressed. Since the inclined surface of the end face cam portion 16a of the needle does not come into contact with the needle anchor drive pin 15, the threading safety plate 16 is pulled downward without being rotated rearward of the sewing machine, and the notch 16c of the threading safety plate 16 is fixed by the needle. It catches on the end of the notch 17a of the hook stand 17. Therefore, the threading lever 42 for the two-needle cannot be pressed any further, so that an erroneous operation can be prevented.

Although the present invention is applied to the overlock sewing machine in the present embodiment, the invention is not limited to this and can be installed in all sewing machines.

[0042]

As is apparent from the above embodiments, in the threading device of the sewing machine of the present invention, the sewing needle is substantially top-dead by the simple operation of lowering the plate member by the threading means. When it is located at the point, the threading claw for threading can be made to face the sewing machine needle and penetrate into the thread hole of the sewing machine needle, and when the sewing machine needle is substantially located other than the top dead center, the threading means is locked. Thus, the threading claw for threading can be prevented from penetrating into the thread hole of the sewing needle. Further, it is possible to prevent the needle retaining drive means from operating during the threading operation. Therefore, regardless of the skill level of the operator, the threading operation can be performed very easily and without erroneous operation.

Also, since the number of parts is small and the mechanism is simple, the assembly is easy and the assembly accuracy is easy to obtain. Therefore, it is possible to provide an inexpensive and high-quality threading device for a sewing machine. . Further, most of the parts of the threading device can be installed on the right side of the sewing needle as viewed from the front of the sewing machine, so that a large working space can be secured and the sewing operation becomes easy.

[Brief description of drawings]

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

FIG. 2 is an exploded perspective view of the threading device of the sewing machine shown in FIG.

FIG. 3 is a perspective view of the sewing machine threading device shown in FIG.
Overall view of a 3-needle overlock sewing machine.

[Fig. 4] Fig. 1 when the sewing machine needle is located at the top dead center.
Of operation of the threading device of the sewing machine shown in FIG.

FIG. 5: FIG. 1 when the sewing machine needle is located at top dead center
Of operation of the threading device of the sewing machine shown in FIG.

FIG. 6 is a view when the sewing machine needle is located at the top dead center.
FIG. 6 is an operation explanatory view showing the relationship among the needle anchor driving pin, the threading safety plate, the threading arm for one needle, and the needle fixing hook of the threading device of the sewing machine shown in FIG.

Fig. 7 Fig. 1 when the sewing machine needle is located at top dead center
FIG. 6 is an operation explanatory view showing the relationship among the needle anchor driving pin, the threading safety plate, the threading arm for one needle, and the needle fixing hook of the threading device of the sewing machine shown in FIG.

8 is an operation diagram showing the relationship between the arm portion of the threading arm for a single needle and the arcuate elongated hole of the threading arm for a single needle of the threading device of the sewing machine shown in FIG.

9 is an operation explanatory view of the threading device of the sewing machine shown in FIG. 1 when the sewing machine needle is located at a position other than the top dead center.

FIG. 10 is a perspective view of a needle anchor drive pin, a threading safety plate, a threading arm for one needle and a needle fixing hook of the threading device of the sewing machine shown in FIG. 1 when the sewing machine needle is located at a position other than the top dead center. FIG. 6 is an operation explanatory view showing a relationship.

FIG. 11 is an exploded perspective view showing another embodiment of the threading device for the sewing machine of the present invention.

12 is an operation explanatory view of a switching means used in the threading device of the sewing machine shown in FIG.

FIG. 13 is a perspective view showing another embodiment of the threading device for the sewing machine of the present invention.

FIG. 14 is an operation explanatory view of the threading device of the sewing machine shown in FIG. 13 when the sewing machine needle is located at the top dead center.

FIG. 15 is an operation explanatory view of the threading device of the sewing machine shown in FIG. 13 when the sewing machine needle is located at the top dead center.

16 is an operation explanatory view of the threading device of the sewing machine shown in FIG. 13 when the sewing machine needle is located at a position other than the top dead center.

[Explanation of symbols]

 1 Sewing machine threading device 6 Sewing machine body 9 ... Needle retainer 10, 10 ', 10 "... Sewing needle 10a, 10'a, 10" a ... Thread hole 14 ... Needle retention drive arm (needle retention drive means) 15 ... Needle retention drive pin 16 ... Threading safety plate (plate-like member) 16a First end cam portion 16b ... Second end cam Portion 16c ... Notch 17 ... Needle fixing hook stand (hook member) 18 ... Threading hook for threading 19, 40 ... Threading means 34 ... Needle fixing hook (needle fixing member) 20 ... Threading set 21, 44 ... threading arm 22, 42 ... threading lever 23 ... threading mount (mounting member) 37 ... threading lever spring (tension spring) 41 ... switching means

Claims (5)

[Claims] 1. A sewing machine main body having a needle retaining drive means for reciprocally driving a needle retainer to which a sewing needle is fixed,
In a threading device of a sewing machine, in which a threading claw for threading is made to face the sewing machine needle and penetrates into a thread hole of the sewing machine needle, in the threading device of the sewing machine, the needle lock is connected to the needle lock driving means and protrudes from the needle lock driving means. A needle retaining drive pin that is provided, a first end face cam portion that engages with the needle retainer drive pin when the sewing machine needle is substantially located at top dead center, and a first end face cam portion that interlocks with the first end face cam portion. A plate-shaped member having two end face cam portions, and the first plate-shaped member fixed to the sewing machine body.
And a hook member on which the second end cam portion of the plate member slides only when the end cam portion of the plate engages with the needle retention drive pin, and the threading thread hook pivotally attached to the plate member. Threading means for causing the claw to face the sewing needle, and the second end cam portion of the plate-shaped member pulls on the hook member when the sewing needle is located substantially other than top dead center. A threading device for a sewing machine, characterized in that a hanging notch is formed. 2. A needle fixing member which is engaged with the plate-like member and which restricts the lowering of the sewing machine needle only when the sewing machine needle is substantially located at the top dead center. Item 2. A threading device for a sewing machine according to Item 1. 3. The threading means includes a threading set having the threading claw for threading, a threading arm to which the threading set is fixed, and a plate-shaped member engaged with the threading arm. 2. A thread for a sewing machine according to claim 1, further comprising: a threading lever that is axially mounted; and a mounting member that is fixed to the sewing machine main body and that has the needle threading arm and the threading lever pivotally attached thereto. Threading device. 4. The threading device for a sewing machine according to claim 1, further comprising a tension spring provided between the hook member and the plate member for constantly biasing the plate member toward the hook member. 5. The threading device for a sewing machine according to claim 1, wherein the threading means is provided with a switching means for positioning the threading claw for threading on any one of a plurality of sewing needles.