JPH06134165A - Sewing machine threading mistake prevention device - Google Patents

Abstract

(57) [Summary] [Objective] When the upper thread tension disc 18 is closed, it is possible to reliably prevent the upper thread from being hung on the upper thread tension disc 18. [Structure] When the presser foot lifting lever 9 is lowered, the thread loosening plate 16 operates, the upper thread tension disc 18 is closed, and
The first link 2 and the second link 6 operate. As a result, the display plate 1 held inside the front surface of the outer cover 8 moves, and the tip portion 1c of the display plate 1 is guided by the guide groove 8b of the outer cover 8.
By closing the upper thread tension plate 18, the upper thread is reliably prevented from being hung on the upper thread tension plate 18 when the upper thread tension plate 18 is closed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a threading mistake preventing device for a sewing machine.

[0002]

2. Description of the Related Art Conventionally, in a sewing machine having a thread loosening mechanism that opens and closes a thread tension disc that applies tension to the upper thread in conjunction with the lifting and lowering operation of a presser foot lifting lever, At the time of performing the operation, the worker lifts the presser foot lifting lever to open the upper thread tension disc and hangs the upper thread on the upper thread tension disc. That is, since the upper thread tension disc is closed when the presser foot lifting lever is lowered, the upper thread is not reliably applied to the upper thread tension disc. Therefore, when hooking the upper thread, the operator lifts the presser foot lifting lever to open the upper thread tension disc to hang the upper thread.

[0003]

However, in the conventional sewing machine, when the operator hooks the upper thread on the sewing machine, the operator has the presser foot lowered and the upper thread tension disc closed. In some cases, the upper thread was hung on without realizing it. In particular, in a sewing machine in which the upper thread tension disc is built in the sewing machine main body, the operator cannot check the open / closed state of the upper thread tension disc from the outside. Therefore, the operator does not notice that the upper thread tension disc is closed, and there is a problem that the upper thread is hung on the outside of the closed upper thread tension disc even when the upper thread tension disc is closed. It was

Further, the operator has not been able to confirm whether or not the upper thread is reliably hooked on the upper thread tension disc.
Therefore, the operator has sewn the upper thread without being surely hooked on the upper thread tension disc.

In this way, if the upper thread is not accurately hung on the upper thread tension disc, it is not possible to apply sufficient tension to the upper thread. Therefore, the tension of the lower thread becomes higher, the tension of the upper thread and the tension of the lower thread are not adjusted, and the upper thread is pulled by the lower thread, so that the sewing cannot be satisfactorily performed. Although the sewing cannot be performed well in this manner, there is also a problem that the operator starts the sewing without noticing that the upper thread is not hooked on the upper thread tension disc.

The present invention has been made to solve the above-mentioned problems. When the upper thread tension disc is closed, the upper thread tension disc cannot hang the upper thread on the sewing machine. The purpose is to provide a protection device.

[0007]

In order to achieve this object, a threading mistake preventing device for a sewing machine according to a first aspect of the present invention is provided with a cloth pressing mechanism for lifting and lowering a presser foot to press a cloth by the operation of a presser foot lifting lever. It is equipped with a thread loosening mechanism that opens and closes the upper thread tension disc that applies tension to the upper thread in conjunction with the operation of the presser foot lifting lever, and further guides the upper thread to hang the upper thread on the upper thread tension disc. A guide groove and a guide groove closing means that interlocks with the operation of the thread loosening mechanism and closes the guide groove when the needle thread tension disc is closed.

Further, the threading mistake prevention device for a sewing machine according to a second aspect of the present invention is provided with a display means for displaying that the upper thread tension disc is closed.

[0009]

In the thread hooking mistake prevention device for a sewing machine according to claim 1 having the above structure, when the thread loosening mechanism is operated in conjunction with the operation of the presser foot lifting lever to close the upper thread tension disc, the guide is provided. The groove closing means closes the guide groove for guiding the upper thread for hooking the upper thread on the upper thread tension disc. Also, when the thread loosening mechanism is operated in conjunction with the operation of the presser foot lifting lever to open the upper thread tension disc, the guide groove closing means is opened to open the guide groove.

In the thread hooking mistake prevention device for a sewing machine according to the second aspect of the present invention, the display means, in conjunction with the guide groove closing means, indicates that the upper thread tension disc is closed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, the structure of the sewing machine provided with the threading mistake prevention device of this embodiment will be described with reference to FIG.

The sewing machine includes a sewing machine bed portion 32, a pedestal portion 34 erected from the right end of the bed portion 32, and an arm portion extending leftward from the pedestal portion 34 so as to face the bed portion 32. 36 and a head portion 38 provided at the tip of the arm portion 36.

Next, the construction of the yarn hooking mistake prevention device of this embodiment will be described with reference to FIGS. 1 and 2.

The yarn threading mistake prevention device of this embodiment has a display plate 1 having display portions 1a and 1b, a first link 2 for operating the display plate 1, and a second link connected to the first link 2.
It is composed of a link 6 and an outer cover 8 of the sewing machine body. The tip 2a of the first link 2 has a bifurcated shape, and the projection 1d formed on the display plate 1 has a tip 2a.
It is fitted to the forked part of. Further, the display plate 1 is held by the exterior cover 8 so as to be movable in the arrow D direction and the counter arrow D direction. In addition, the first link and the second link 6 are linked by a shaft 7 so as to be interlocked with each other, and the base plate 4 is attached to the first link 2 by the shaft 3. It is possible to move to the center. Then, the other end of the Hiki spring 5, one end of which is attached to the protruding portion 4a of the base plate 4, is attached to the tip end portion 2a side of the first link 2, and the first link 2 is biased toward the protruding portion 4a side. ing.

Further, as shown in FIG. 5, a display window 8 for displaying the display portions 1a and 1b of the display plate 1 to an operator is provided on the front upper portion of the exterior cover 8 of the arm portion 36 of the sewing machine main body.
a and a guide groove 8b for guiding the upper thread for hanging the upper thread on the upper thread tension disc 18. On the display plate 1 displayed in the display window 8a, as shown in FIGS. 2 and 4, the display unit 1a showing a state where the presser foot lifting lever 9 is raised, that is, a state where the thread tension disc is opened, Further, a display portion 1b is provided which shows a state where the presser foot lifting lever 9 is lowered, that is, a state where the thread tension disc is closed.

As shown in FIG. 3, the presser foot mechanism includes a presser bar lifting lever 9 rotatable about a shaft 10, a presser bar 11, and a presser bar attached to the presser bar 11 by a mounting screw 13. It is composed of feet 12. To the presser bar 11, a presser bar hanger 14 that moves up and down by the operation of the presser bar lifting lever 9 is fixed by a screw 15.

Further, as shown in FIGS. 1 and 3, the thread loosening mechanism has a thread loosening plate 1 which is interlocked with the rotation of the presser foot lifting lever 9.
6 and an upper thread tension mechanism 30. The thread loosening plate 16 is rotatable around a shaft 17 fixed to the back surface 33 of the arm portion 36. The upper thread tension mechanism 30 includes a thread loosening bar 19 that opens and closes the upper thread tension disc 18.
An upper thread tension spring 20 for applying pressure to the upper thread tension disc 18 in the closing direction of the upper thread tension disc 18, and a spring seat 21 for uniformly transmitting the pressure of the thread tension spring 20 to the upper thread tension disc 18. Has been done. The spring seat 21 is slidable with respect to the spring shaft 20a.

The engaging portion 6 provided at the tip of the thread loosening plate 16 is fitted into the engaging hole 6a provided at the tip of the second link 6.
6a is engaged. Then, the end portion 1 of the thread loosening bar 19
9a is slidably held between the engaging portion 16a and a holding portion 16b provided at an end extending from the engaging portion 16a. In this way, the second link 6 and the thread loosening plate 1
6 and the thread loosening bar 19 are interlockably connected. Further, the pressing portion 19b at the tip of the thread loosening bar 19 has the spring seat 21
The upper thread tension spring 20 can be compressed in the arrow C direction.

Here, the upper thread tension disc 18 is biased in the direction opposite to the arrow C direction by the upper thread tension spring 20 via the spring seat 21. Therefore, when the presser bar lifting lever 9 is lowered, as shown in FIG.
Is closed by the urging force of the upper thread tension spring 20. On the other hand, when the presser foot lifting lever 9 is raised, the spring seat 21
Since the pushing portion 19b of the thread loosening bar 19 pushes and moves in the direction of arrow C, the upper thread tension spring 20 is also pushed in the direction of arrow C. As a result, the needle thread tension disc 18 moves toward the upper thread tension spring 2
It is no longer biased by 0 and is released.

Next, the operation of the yarn hooking mistake prevention device of this embodiment will be described with reference to FIGS.

First, the operator pushes the presser foot lifting lever 9 into the shaft 10
3 is rotated in the direction of arrow A shown in FIG. 3, the end portion 14a of the presser bar hanger 14 rides on the cam portion 9a of the presser bar lifting lever 9, and the presser bar 11 and the presser foot 12 are
As indicated by the chain double-dashed line, the arm 36 moves up along a guide hole (not shown). Further, with the rotation of the presser foot lifting lever 9 in the direction of arrow A, the thread loosening plate 16 moves in the direction of arrow B around the shaft 17 and the end portion 16a of the thread loosening plate 16 is moved.
Rides on the cam portion 9b of the presser foot lifting lever 9 and enters the state shown by the chain double-dashed line in FIG.

When the thread loosening plate 19 also moves in the direction of arrow B in FIG. 1 along with the movement of the thread loosening plate 16 in the direction of arrow B, the pressing portion 19b of the thread loosening plate 19 pushes the spring seat 21 in the direction of arrow C. . Then, the spring seat 21 moves in the direction of arrow C and pushes the upper thread tension spring 20 in the direction of arrow C, and the upper thread tension spring 20 is compressed. As a result, the upper thread tension disc 18 is released from the bias from the upper thread tension spring 20 and the upper thread tension disc 18 is released.
Is released. As described above, by the operation of the presser foot lifting lever 9, the presser bar 11 and the presser foot 12 are moved up and down, and the needle thread tension disc 18 is opened and closed.

Further, as the yarn loosening plate 16 moves in the direction of arrow B, the second link 6 also moves in the direction of arrow B, as shown by the chain double-dashed line in FIG. Then, along with the movement of the second link 6, the first link 2 rotates counterclockwise around the shaft 3, and the display plate 1 also moves in the direction of arrow D.

Then, the operator can visually recognize the display portion 1a or the display portion 1b from the display window 8a of the exterior cover 8. That is, when the hold-up lever 9 is lowered, that is, in the state shown by the solid line in FIGS. 1 and 3,
A display portion 1b indicating that the thread tension disc is closed is displayed from the display window 8a. On the other hand, when the hold-up lever 9 is raised, that is, in the state shown by the dotted lines in FIGS. 1 and 3, the display portion 1a indicating that the thread tension disc is opened from the display window 8a is displayed. Therefore, the operator can visually check the display of the display window 8a as to whether or not the hold-up lever 9 is in the up-and-down state, that is, whether or not the upper thread can be hung on the upper thread tension disc.

Further, as the hold-up lever 9 is moved up and down, the tip portion 1c of the display plate 1 is guided by the guide groove 8b of the exterior cover 8.
It is possible to open and close. That is, when the press-up lever 9 is lowered and the display plate 1 moves in the direction of arrow D, the guide groove 8b of the exterior cover 8 is closed by the tip portion 1c of the display plate 1. On the other hand, when the holding lever 9 is raised and the display plate 1 moves in the direction of arrow D, the display plate 1
The guide groove 8b of the outer cover 8 is opened by the tip portion 1c of the.

As described above, when the press-up lever 9 is lowered, the guide groove 8 is moved by the tip portion 1c of the display plate 1.
Since b is closed, the operator cannot hang the upper thread on the upper thread tension disc. Therefore, it is possible to reliably prevent the thread hooking mistake on the needle thread tension disc with the simple configuration as described above.

Further, instead of providing the display portions 1a and 1b on the display plate 1, the front end portion 1c of the display plate 1 is colored to indicate the presence of the front end portion 1c of the display plate 1 in the guide groove 8b of the outer cover 8. You may.

The present invention is not limited to the above-mentioned embodiments, and modifications can be made without departing from the spirit of the present invention.

[0030]

As is apparent from the above description, in the threading mistake prevention device for the sewing machine of the present invention, the thread is hung on the needle thread tension disc when the needle thread tension disc is closed. It can be surely prevented.

[Brief description of drawings]

FIG. 1 is a top view showing a threading mistake prevention device of the present embodiment.

FIG. 2 is a diagram showing a display plate and an exterior cover of the yarn hooking mistake prevention device of the present embodiment.

FIG. 3 is a diagram showing a cloth pressing mechanism in the yarn hooking mistake prevention device of the present embodiment.

FIG. 4 is a diagram showing a display unit of the yarn hooking mistake prevention device of the present embodiment.

FIG. 5 is a front view of a sewing machine provided with a threading mistake prevention device of this embodiment.

[Explanation of symbols]

 1 display plate 1a display part 1b display part 1c tip part 2 first link 6 second link 8 exterior cover 8b guide groove 9 presser foot lifting lever 12 presser foot 18 upper thread tension plate

Claims (2)

[Claims] 1. A presser foot mechanism that moves a presser foot up and down to press a cloth by the operation of a presser foot lifting lever, and an opening and closing of a needle thread tension plate that applies tension to the upper thread in conjunction with the operation of the presser foot lifting lever. In a sewing machine that is equipped with a thread loosening mechanism for performing, and in which the upper thread is engaged with the upper thread tension tray when the upper thread tension tray is opened, a guide groove for guiding the upper thread to hang the upper thread on the upper thread tension tray is provided. A guide groove closing means for closing the guide groove in conjunction with the operation of the thread loosening mechanism, wherein the guide groove closing means closes the guide groove when the upper thread tension disc is closed. Sewing machine threading mistake prevention device characterized by the above. 2. The thread hooking error of the sewing machine according to claim 1, further comprising display means for displaying that the upper thread tension disc is closed, in conjunction with the guide groove closing means. Prevention device.