JPH0596076A - Device and method for damping bobbin thread bobbin of sewing machine - Google Patents

Abstract

PURPOSE:To obstruct idle running of a bobbin thread bobbin, and to prevent generation of the idle running by providing a damping member in a specific range part in the radial direction moving control direction of the bobbin thread bobbin of a bobbin supporting part. CONSTITUTION:In a state that a bobbin thread T is drawn out normally by a bobbin thread bobbin 4, the bobbin thread bobbin 4 is drawn closer to the drawing-out direction C of a thread, therefore, on the anti-drawing-out side of the bobbin thread bobbin 4, a cavity part is generated against an inside wall 6 of a bobbin thread containing recessed part 2. Also, a contact of the outside peripheral, part 5 of the bobbin thread bobbin 4 and the inside wall 6 moves within a prescribed range, therefore, a cavity part of the opposite side of drawing out a thread also moves. When the bobbin thread bobbin moves in a normal state, the minimum cavity part is generated. To the inside wall which faces the cavity part in this normal state, a thin tape-like clamping member 16 whose friction coefficient is large such as a urethane rubber material is stuck, or provided integrally by two-color molding. That is, the clamping member 16 does not work on the bobbin thread bobbin 4 in a normal state of the bobbin thread bobbin, works only at the time when it becomes a floating state and returns it quickly to a normal state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking device for a bobbin bobbin which holds a bobbin thread of a sewing machine which constitutes a lock stitch composed of an upper thread and a bobbin thread.

[0002]

2. Description of the Related Art A conventional bobbin bobbin holding structure of a lockstitch sewing machine has a bobbin accommodating chamber 2 of an inner hook 1 as shown in FIG. The outer periphery 5 of the bobbin 4 is surrounded by the inner wall 6 of the bobbin storage chamber 2 so as to restrict the movement in the radial direction, and most of them are intended for a horizontal hook. Idling of the bobbin thread bobbin does not occur in applications where a small amount of sewing thread is used such as straight-line stitching that is usually used, but it occurs during high-speed sewing when a large amount of sewing thread is used such as decorative ZZ stitch. In the stitch structure shown in the figure, the unfolding amount of the lower thread as indicated by the point A and the stitching failure such as the appearance of the lower thread as indicated by the point B in the figure occur.

The sewing failure is caused by the bobbin drive resistance being invalidated by the bobbin idling out of the drive resistance of the bobbin and the bobbin thread tension spring 14 (FIG. 4) which are the elements for applying the bobbin thread tension. It is caused by lowering the lower thread tension. In the old type vertical hook SA as shown in FIG. 3 in which the bobbin to be housed is hard to see, a bobbin case for holding the lower thread bobbin is loaded in the hook, and the side surface 10 of the bobbin 9 is loaded by the spring 8 in the bobbin case. The method of pressing and braking was the most effective and was widely used. However, if this method is applied to the horizontal hook, the tension applied to the sewing thread by the rotation resistance of the bobbin 4 will be described with reference to FIG. 5, and from the rotation center 12 of the position 11 where the bobbin thread T separates from the bobbin 4. Distance L
However, there is a drawback that the stitch tone varies as a result. Further, in the above-mentioned horizontal hook, the side surface 1 of the bobbin is used.
A structure in which 3 (FIG. 1) is pressed by a spring from above is impossible because the upper thread passes therethrough, and in reality there is no effective preventive measure. Although a structure in which a magnet or the like is used to give a braking action to the bobbin bobbin has been considered, there is a restriction that the bobbin must be made of a magnetic material.

[0004]

SUMMARY OF THE INVENTION According to the present invention, in a horizontal hook for holding a bobbin thread bobbin of a sewing machine, which is lock stitched with the above-mentioned upper thread and bobbin thread, the bobbin thread bobbin is braked in the radial direction, and the bobbin bobbin is unattended. This is intended to prevent idling rotation.

[0005]

According to the present invention, as a result of analyzing the idling rotation state of the horizontal hook, the bobbin is in a floating state when the bobbin idles, and in the normal rotation state, the thread withdrawing direction from the bobbin thread bobbin. C (Fig. 5) The contact portion between the outer peripheral portion of the bobbin indicated by the arrow and the inner wall (radial direction regulating member) of the bobbin storage chamber is within a certain range, but the contact portion is not fixed within a certain range and is unspecified. It was Focusing on this point, the present invention has been able to achieve a sufficient effect for preventing idle rotation of the bobbin bobbin by providing a braking member having a large friction coefficient in a region other than a certain range related to the contact portion in a normal rotation state. That is, as shown in FIG. 5, a braking member having a large friction coefficient is provided on the inner wall of the bobbin accommodating chamber which serves as a radial direction regulating member of the lower thread bobbin and the outer peripheral portion of the lower thread bobbin in the normal rotation state of the lower thread bobbin. It is characterized in that it is provided in other portions except the contact portion within the range.

[0006]

From a bobbin thread bobbin which is supported by the lower surface and which is restricted in radial movement, a bobbin thread of the sewing threads necessary for forming the stitches of the lock stitch composed of the upper thread and the bobbin thread is rotatable. In the sewing machine to be supplied, the braking member for preventing the idling rotation of the bobbin is installed in the bobbin supporting portion in the bobbin radial direction movement restricting direction, and the installation position of the braking member is the bobbin and the bobbin accommodating portion in a normal state in which idling rotation does not occur. By providing the bobbin bobbin in a specific range except the contact position with the inner wall, when the bobbin bobbin separates from the bobbin storage chamber inner wall on the bobbin thread pull-out side, braking is prevented to prevent idling of the bobbin thread bobbin. It is characterized by preventing.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. On a bed machine frame, which is supported by the arm machine frame of the sewing machine and is vertically moved, corresponding to a lower position of the needle bar, is provided a thread catching portion that cooperates with a needle fixed to the lower end of the needle bar. Is composed of a rotating horizontal shuttle S, an inner shuttle 1 which is held inside the horizontal shuttle to prevent rotation, and a lower thread bobbin 4 which is housed in a lower thread receiving recess 2 formed in the inner shuttle. To be done.

The inner hook 1 is provided with a tension applying device 14 for applying a tension when the bobbin thread T wound around the bobbin bobbin 4 is pulled out. In the thrust direction of the lower thread accommodating recess 2 of the inner hook 1, one is the bottom, the other is open, and the lower thread bobbin 4 is provided.
The movement of the lower thread bobbin 4 in the radial direction is regulated so that the outer peripheral portion 5 is surrounded by the inner wall 6 of the lower thread accommodating recess 2.

The bobbin thread T drawn from the bobbin thread bobbin 4 is drawn toward the tension applying device 14 provided on the inner wall 6 of the inner hook 1, and is passed through the spring pressurizing portion in the tension applying device to the outside. It is pulled out to the side and guided to the needle insertion hole of the needle plate fixed to the bed surface. Bobbin thread T is bobbin thread 4
In a state where the lower thread bobbin 4 is more normally pulled out, the lower thread bobbin 4 is pulled in the thread withdrawing direction (FIG. 5C). Voids are created. When the lower thread T is normally pulled out, the contact point between the outer peripheral portion 5 and the inner wall 6 of the lower thread bobbin moves within a certain range, for example, from the pulling point P of the tension applying device 14 to the needle piercing hole of the needle plate. Since the angle fluctuates within a range of α ° toward the near side and β ° toward the far side (α ° is approximately 30 °, β ° is approximately 60 °), the void portion on the opposite side of the yarn drawing also moves. When the bobbin bobbin moves in a normal state, a minimum gap is created. A braking member 16 in the form of a thin tape having a large friction coefficient, such as a urethane rubber material, is adhered to the inner wall facing the void portion in the normal state, or integrally formed by two-color molding.

Since one embodiment of the present invention has the above-mentioned structure, the conventional structure is likely to cause the bobbin bobbin to idle and rotate in addition to the normal drawing state. Since the bobbin 4 does not come into contact with the braking member 16, the bobbin 4 does not come into contact with the braking member 16 because the braking member 16 is provided on the inner wall of the yarn accommodating recess, and the sewing machine decelerates or stops to cause the bobbin thread bobbin to idle. Only when it is attempted to do so, the bobbin bobbin itself comes into contact with the braking member 16 due to the motion, and the braking action stops the motion within a very short time to restore the normal state. Idling is prevented.

In other words, the braking member 16 does not act on the bobbin thread bobbin 4 in a normal state of the bobbin thread bobbin, but acts only when the bobbin thread bobbin is in a floating state to promptly restore the normal state. The large braking member 16 can be used without any side effect, and a great effect is produced. In addition, the installation position of the braking member may be a part of the void portion instead of the entire void portion formed on the opposite side of the contact position in the normal state.

[0012]

[Effect] Since the present invention has the above-mentioned construction and action, it is constituted by the upper thread and the lower thread by preventing the idle rotation of the lower thread bobbin by providing the inner wall with the braking member. There is no irregularity in the regular seams, and it is possible to obtain beautiful seams at all times, which is a great practical effect.

[0013]

[Brief description of drawings]

FIG. 1 is a perspective view of a horizontal hook that is a conventional thread catching portion for carrying out the present invention, FIG. 2 is a structural diagram of a stitch formed by a conventional device, and FIG.
Is a cross-sectional view of the vertical pot, FIG. 4 is a perspective view of the device of the present invention, and FIG.
Is a plan view of the present invention. T is the lower thread 2 is the lower thread accommodating portion 6 is the inner wall 16 is the braking member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takanori Igarashi 3-1-1, Kyobashi, Chuo-ku, Tokyo Janome Eye Machinery Co., Ltd.

Claims (2)

[Claims] 1. A lower thread of a sewing thread necessary for forming a seam of a lock stitch composed of an upper thread and a lower thread is axially restricted by a lower surface of a recess and radially restricted by a side wall of the recess. In a sewing machine supplied from a lower thread bobbin rotatably supported, a braking member for preventing idling rotation of the lower thread bobbin is installed in a radial direction movement restricting direction of the lower thread bobbin of a bobbin supporting portion, and A bobbin braking device for a sewing machine, characterized in that an installation position is set to a portion other than a contact range between the bobbin in a normal state in which idle rotation does not occur and the bobbin radial direction regulating member. 2. A lower thread of one of the sewing threads necessary for forming a seam of a lock stitch constituted by an upper thread and a lower thread is axially restricted by a lower surface of the recess and a radial direction is restricted by a side wall of the recess. In a sewing machine supplied from a bobbin thread bobbin that is rotatably supported, a braking member that prevents idle rotation of the bobbin thread bobbin is installed in the radial movement restricting direction of the bobbin bobbin of the bobbin supporting portion, and A method for braking a bobbin bobbin of a sewing machine, wherein an installation position is set to a portion excluding a contact range between the bobbin and the radial regulation member in a normal state where idling rotation does not occur.