JPH0552756B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a horizontal hook for a sewing machine having a hook axis formed perpendicular to the rotating surfaces of a bobbin case and an outer hook.

[Conventional technology]

4 to 7 are explanatory diagrams showing a conventional horizontal hook and horizontal hook device for a sewing machine. Figure 4 is a perspective view of the horizontal hook, Figure 5 is an exploded perspective view showing the horizontal hook and horizontal hook device, Figure 6 is a perspective view of the throat plate, and Figure 7 is how the horizontal hook is installed on a two-needle sewing machine. FIG.
Here, the configuration of a conventional horizontal hook and horizontal hook device for a sewing machine will be explained with reference to these figures.

As shown in FIGS. 4 and 5, the horizontal hook is composed of a bobbin case 1 with a closed upper opening, an inner hook 2, and an outer hook 3. The bobbin case 1 is provided with an opener 4 on the outer edge of the upper surface, and an inner hook 2 on the outer peripheral wall.
A connecting groove 5 into which a bobbin case support 20 (described later) fits is provided in the center of the upper surface.
A bobbin support hole 6 into which the bobbin thread 1 fits is provided, and a slit-shaped thread take-out port 7 from which the bobbin thread is taken out is provided on the outside. The bobbin thread outlet 7 is a groove through which the thread of a bobbin (not shown) installed in the bobbin case 1 is taken out to the outside of the bobbin case 1.
It is applied from the bottom of the outer peripheral wall to the middle part. A tension spring 8 is fixed to the outer surface of the bobbin thread outlet 7 with screws 9 and 10 so as to cover the bobbin thread outlet 7. There are two types of tension springs 8, one with a fork-shaped tip and the other with a flat tip, and FIG. 5 shows the flat-shaped one. The lower thread from the bobbin via the lower thread outlet 7 is pulled out along the outer periphery of the bobbin case 1 inside the tension spring 8, and the spring force of the tension spring 8 acts as tension. This tension is adjusted to a predetermined tension by tightening or loosening the screw 9. When installing the bobbin case 1 and the inner pot 2, the connecting groove 5 is connected to the bobbin case support 20, and the bobbin support hole 6 is connected to the bobbin support 2.
1, respectively. The bobbin case support 20 is a screen-like support provided on the periphery of the inner hook 2, and an inner hook stopper 22 is provided at the upper end.
is being carried out. This inner hook stopper 22 is a projection made in the horizontal direction, and is attached to the throat plate 23 shown in FIG.
The inner hook 2 is fitted into the stopper groove 24 to prevent the inner pot 2 from rotating. The stopper groove 24 is a groove formed in a gap between two stoppers 24a and 24b provided on the back surface of the throat plate 23. The bobbin support 21 is a support shaft provided at the center of the bottom surface of the inner hook 2, and is constructed integrally with the inner hook 2. A bobbin presser 25 is provided at the upper end of the bobbin support 21, and this is a claw for attaching and detaching the bobbin case 1.
The bobbin case 1 can be removed by standing the claw vertically using the spring inside the cylinder, and the bobbin case 1 can be prevented from coming off by tilting the claw horizontally. A protruding race 26 is provided on the outer periphery of the inner hook 2 except for a predetermined portion, and is fitted into a groove of the outer hook 3, which will be described later.

The outer hook 3 is provided with a tip 30, a race groove 31, and a hook shaft 36. The tip 30 is a thread loop capturing pawl that captures a loop formed in the upper thread and rotates around the outer circumference of the inner hook 2 to form a stitch with the lower thread. The race groove 31 is the race 2 of the inner pot 2.
6 is the groove that fits, and the inner pot retainer 32 is the screw 3.
3a and 33b are fixed to the upper surface of the outer hook 3. A back plate 34 is fixed to the outer bottom surface of the outer pot 3 with screws 35a and 35b. Pot shaft 36
The outer hook 3 rotates from the lower shaft (not shown) of the sewing machine.
At the same time, it has the function of operating an opener, which will be described later. For this purpose, an eccentric shaft 37 is integrally formed on the upper part of the hook shaft 36. Also, pot shaft 3
A through hole 38 is provided in the 6, which also has the function of supplying lubricating oil to the race portion through an oil string attached therein.

On the other hand, the horizontal hook device is constructed by adding an opener mechanism to the above-mentioned horizontal hook.As shown in FIG. 5, the opener mechanism consists of an opener 40, an opener support 41, and a connecting rod 42. The connecting rod 42 is an arm that interlocks the outer hook 3 and the opener support 41. One of the two rings is fitted onto the eccentric shaft 37, and the other is connected to the swinging fulcrum 45 of the opener support 41 using a stepped screw 43 and a nut 44. Fixed with loose fit. The opener 40 is attached to the arm portion of the opener support 41 with a screw 46, and an opener support shaft 48 is fitted into a ring 47 that serves as a fulcrum of the opener support 41. This shaft 48 is fixed with a screw to a hook stand (not shown) fixed to the sewing machine bed.

The horizontal hook device constructed as described above is mounted on a sewing machine bed (not shown) as shown in FIG. As can be seen from FIG. 7, the opener 40 corresponds to the opener 4 of the inner pot 2 in the positional relationship shown in the figure. A feed dog 50 is positioned in the hole of the throat plate 23. This feed dog is fixed to a feed base (not shown) of the sewing machine feed mechanism, and forms an elliptical feed movement in synchronization with the needle movement. This movement acts on the sewing item mounted between the pressing mechanism and the sewing item, thereby feeding the sewing item. A needle hole 51 is provided in the center of the feed dog 50.

Next, the operation of the horizontal hook and opener mechanism will be explained. In FIG. 7, when the sewing machine is rotationally driven, the outer hook 3 rotates fully in the direction of arrow A (clockwise), and the opener 40 is moved between the screws 43, 46 and the opener support shaft 48 with the opener support shaft 48 as the fulcrum. It swings in the directions of arrows B and C by an angle determined by the pitch length and the amount of eccentricity of the eccentric shaft 37. This swinging motion of the opener 40 allows the upper thread from the needle to easily pass through the inner hook stop 22 and to pass around the outer periphery of the bobbin case 1 and the inner hook 2.

This situation will be explained in detail with reference to FIGS. 8-10.

Fig. 8 is a model plan view of the horizontal hook to explain the progress of the upper thread, Fig. 9 is a plan view showing the situation in which the bobbin thread is fed out, and Fig. 10 is a cross-sectional view on the DD plane of Fig. 8. It is. In FIG. 8, reference numeral 60 indicates an upper thread, which is shown running around the outer periphery of the bobbin case 1 and the inner hook 2. That is, as the tip 30 (FIG. 5) of the outer hook 2, which captures the loop of the needle thread formed by the needle thread, rotates in the direction of arrow A, the needle thread 60
The ring sequentially moves from position 60a to position 60b. Position 60a indicates the moment when the needle thread 60 from the needle hole 51 is about to come off the stopper 24a of the needle plate 23 and enter the stopper groove 24. At this time, the opener 40 is moved by the arrow C in FIG.
maximum displacement in the direction. Along with this, the inner pot 2 also swings in the direction of arrow C in FIG.
2 is forcibly moved from the position shown by the solid line to the position 22a shown by the broken line, and a gap is created between the inner pot stopper 22 and the stopper 24a. By the way, inner pot 2
is always subjected to a rotational force in the direction of arrow A due to the frictional force at the contact portion with the outer hook 3, that is, the race portion, and as a result, the inner hook stopper 22 always tries to be pressed against the stopper 24a while the sewing machine is running. . This pressing force will be further increased by letting out the bobbin thread. In other words, in Fig. 9, the bobbin thread 6 is paid out from the bobbin.
1, the position of the bobbin thread outlet 7 of the bobbin case 1 is clockwise of the outer hook 3 with respect to the line connecting the center of the bobbin support 21 that fits into the bobbin support hole 6 and the inner hook stopper 22. Since the rotation is within two right angle ranges in the counterclockwise direction, the tension of the lower thread 61 that is fed out acts in a direction that rotates the inner hook 2 in the direction of the arrow A. As mentioned above, the tension spring 8 normally applies a static tension of 30 to 100 g to the bobbin thread 61, and this tension increases when the bobbin thread 61 is paid out at high speed. Dynamic tension can occur. On the other hand, the pressing force due to the friction of the outer hook 3 is also approximately the same, so that the inner hook stopper 22 during sewing is pressed against the stopper 24a by the sum of these pressing forces of 60 to 200 g. The opener 40 swings the inner hook 2 in the direction of arrow C against this pressing force, and due to this forced movement, the needle thread 60c on the needle side moves from the solid line position to the broken line position 60d as shown in FIG. Then, it passes through the inner pot stopper 22 and begins to rotate around the outer periphery of the inner pot 2. In other words, if the opener did not operate in this way, abnormal tension would be applied when the needle thread 60a passes through the inner hook stopper 22, and a towel-like needle thread loop would occur on the back side of the sewing product. Put it away. After that, the rotation continues further and upper thread 6
0 reaches the position 60b in FIG.
0 has the maximum displacement in the direction of arrow B, and accordingly, the loop of the upper thread 60 easily passes through the gap between the inner hook stopper 22 and the stopper 24b of the throat plate 23, and finishes turning around the outer periphery of the inner hook 2. . And the upper thread 60 is the lower thread 61
and intertwine to form a seam.

[Problem that the invention seeks to solve]

As mentioned above, the opener mechanism is indispensable for the horizontal hook of conventional sewing machines, and as a result, the opener and the bobbin case hit each other, and the inner hook stopper and the needle stopper collide when the horizontal hook rotates at high speed, causing noise. It was becoming. In particular, as the speed of sewing machines increases, the noise level becomes more noticeable, which significantly impedes the operability of sewing machines for sewing workers. Furthermore, there is a problem in that collision between the inner pot stopper and the stopper of the throat plate sometimes causes fatigue failure of the inner hook stopper.

The present invention has been made to solve these problems, and an object thereof is to obtain a horizontal hook for a sewing machine that can reduce noise by eliminating the opener mechanism by changing the structure of the horizontal hook.

[Means for solving problems]

In the horizontal hook of the sewing machine according to the present invention, the bobbin thread outlet of the bobbin case is provided within two perpendicular ranges in the rotational direction of the outer hook with reference to the line segment connecting the center of the bobbin support and the inner hook stop, and the hook axis of the horizontal hook is provided. have the same diameter.

[Effect]

In the present invention, in order to reduce the noise caused by the opener and the bobbin case hitting the opener due to the high speed rotation of the horizontal hook, and the noise from the inner hook stopper and throat plate stopper due to the lower thread feeding tension of the horizontal hook, the bobbin thread is The feeding tension is applied in the opposite direction to the pressing force generated in the rotational direction of the outer hook, so that the upper thread passes through the inner hook stopper portion without operating the opener mechanism, and the above-mentioned noise is suppressed.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3. FIGS. 1 and 3 are perspective views showing the bobbin case, and FIG. 2 is a plan view of the horizontal hook for explaining how the bobbin thread is paid out. In Figures 1 to 3, the symbols in the figures refer to Figures 4 to 10.
Shows parts that are the same as or equivalent to those in the illustration. As shown in FIG. 1, the present invention is characterized in that the opener 4 shown in the prior art is eliminated from the bobbin case 1, and the position of the bobbin thread outlet 7 is changed. The position of the bobbin thread outlet 7 is based on a line segment connecting the center of the bobbin support 21 that fits into the bobbin support hole 6 when the bobbin case 1 is attached to the inner hook 2 and the inner hook stop 22 provided in the inner hook 2. 2 by rotating the outer pot 1 clockwise.
A lower thread outlet 7 is provided in the bobbin case 1 within a perpendicular range. As shown in FIG. 1, the bobbin thread outlet 7 is formed in the shape of a slit in the outer circumferential wall of the bobbin case 1 from the edge bottom to the middle portion. A tension spring 8 or 8a is fixed to the outer surface of the bobbin case 1 by screws 9 and 10 so as to cover the lower thread outlet 7. There are two types of tension springs depending on their shape: a flat type shown in 8 and a two-pronged type shown in 8a. The two-pronged tension spring 8a has a bifurcated tip, and when fastened to the bobbin case 1, the tip is fitted into the tension spring support hole 8b. The spring force of the tension spring 8 is exerted by tightening and loosening the screw 9.

According to the present invention, the outer pot 3 has an opener 40,
Horizontal hook devices such as the opener support 41, the connecting rod 42, and the opener support shaft 48 are no longer required, and the eccentric shaft 37 integrally formed with the hook shaft 36 shown in the outer hook 3 of the conventional horizontal hook can be removed. The hook shaft 36 that causes the outer hook 3 to rotate from the lower shaft of the sewing machine can be configured to have the same diameter.

Next, the effect will be explained.

In FIG. 2, when the sewing machine is rotated, the outer hook 3 is rotated in the direction of arrow A. On the other hand, the bobbin thread 61 taken out from the bobbin (not shown) through the bobbin thread outlet 7 is let out in a direction where its tension causes the inner hook 2 to rotate in the direction opposite to the arrow A. As a result, the pressing force of the throat plate 23 on the stopper 24a acting on the inner hook stopper 22 is substantially reduced to zero because the frictional force of the outer hook 3 against the inner hook 2 and the tension caused by the feeding of the bobbin thread 61 cancel each other out. becomes. The outer circumference of the inner hook for the upper thread is as explained in FIG. 10, but in the case of FIG.
Since the pressing force on 4b will hardly act,
The upper thread 60 can easily move around the outer circumference of the inner hook 2 without operating the opener mechanism.

FIG. 3 is a perspective view of a bobbin case 1 used in a corner stitch sewing machine among two-needle lockstitch sewing machines. In this case as well, except for the parts having the same structure as the conventional bobbin case, the structure and operation of the present invention are as explained in FIGS. 1 and 2.

In Fig. 3, 11 and 12 are bobbin thread feeding grooves, 13 is a bobbin thread slack prevention spring, and 14 is a bobbin thread through hole.This example shows the bobbin case 1 when the outer hook 3 rotates clockwise. There is. A tension spring 8 is provided on the outer surface of the bobbin case 1 so as to cover the bobbin thread outlet 7.
is fixed with screws 9 and 10. As shown in FIG. 3, the bobbin thread from the bobbin (not shown) passed through the inside of the tension spring 8 is further passed through two bobbin thread payout grooves 11 and 12, a bobbin thread slack prevention spring 13, and a bobbin thread. It is pulled out through the through hole 14. The bobbin thread feeding grooves 11 and 12, the bobbin thread slack prevention spring 13, and the bobbin thread threading hole 11 are conventional components for corner stitching.

Although the above embodiment shows the case where the outer hook 3 rotates clockwise, even in a horizontal hook where the outer hook 3 rotates counterclockwise, the position of the bobbin thread outlet 7 of the bobbin case 1 is located at the bobbin support hole. When the outer hook 3 is rotated counterclockwise, the bobbin case near the bobbin thread outlet 7 A tension spring 8 or 8a is fixed to the outer surface of the thread outlet 7 by screws 9 and 10 so as to cover the lower thread outlet 7.

〔Effect of the invention〕

As explained above, the present invention has a structure in which the rotational force applied to the inner hook by the bobbin thread is applied in the opposite direction to the rotational force due to friction of the outer hook, thereby eliminating the need for an opener mechanism that requires complicated machining. A simple and inexpensive horizontal pot device can be obtained.
Further, noise caused by the collision between the opener, the inner hook stopper, and the throat plate can be eliminated, and fatigue damage caused by the collision between the inner hook stopper and the throat plate can be prevented.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention. FIGS. 1 and 3 are perspective views of a bobbin case, FIG. 2 is an explanatory diagram showing the operation of the present invention, and FIGS. 7
The figure is a block diagram of a conventional horizontal hook and horizontal hook device, and FIGS. 8 to 10 are explanatory diagrams showing the operations of FIGS. 4 to 7. In the figure, 1 is the bobbin case, 2 is the inner pot, and 3 is the bobbin case.
is the outer hook, 6 is the bobbin support hole, 7 is the bobbin thread outlet,
8 is a tension spring, 21 is a bobbin support, 22 is an inner hook stopper, and 36 is a hook shaft. In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. An inner hook having a bobbin case support with a bobbin support protruding from the center of the bottom surface and an inner hook stopper projecting horizontally on the periphery, and a bobbin that fits into the bobbin support at the center of the top surface. A support hole is provided, the outer peripheral wall is provided with a connecting groove that fits into the bobbin case support, a bobbin thread take-out port, and a tension spring that covers the bobbin thread take-out port, and an upper opening that can be detachably attached to the inner hook is closed. In the horizontal hook of a sewing machine, the sewing machine is composed of a cylindrical bobbin case, an outer hook loosely fitted to the outer periphery of the inner hook so as to be relatively rotatable, and a hook shaft formed perpendicular to the rotating surface of the outer hook. A horizontal hook for a sewing machine, characterized in that a bobbin thread outlet of the bobbin case is provided within two perpendicular ranges in the rotational direction of the outer hook with reference to a line segment connecting the center of the bobbin support and the inner hook stop.