JPH0225639B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a vertical full-rotation hook that can be suitably implemented in a lockstitch sewing machine or the like.

Prior Art FIG. 5 is a sectional view of a vertical full-rotation kettle 1 showing a typical prior art, and FIG. 6 is a cross-sectional view of a vertical full-rotation kettle 1 showing a typical prior art.
It is a perspective view of the bobbin 5 attached to. BACKGROUND ART Conventionally, in a vertical full-rotation hook 1 used in a lockstitch sewing machine or the like, an inner hook 3 having the same axis is housed within an outer hook 2 that is rotatable about a rotation axis. Inside the inner hook 3 is a bobbin 5 on which the bobbin thread 4 is wound.
A bobbin case 6 for storing the is attached. The bobbin 5 of such a vertical full-rotation hook 1 usually has a length of 40 m.
In particular, in industrial electric sewing machines, the torque of the drive motor is large and the sewing speed is fast, so the bobbin thread 4 wound around the bobbin 5 is
will be used up in a short time. When the bobbin thread 4 of this bobbin 5 is used up, the operator must stop the sewing machine and replace the bobbin 5 with another bobbin 5 that has already been wound with a new bobbin thread. Therefore, the sewing operation must be frequently interrupted in order to replace the bobbin.

In order to solve the above-mentioned problem, it has conventionally been desired to increase the amount of winding of the bobbin thread. In order to increase the amount of winding of the bobbin thread, as shown in FIG.
There are two possible methods: (b) increasing the diameter D1 of the bobbin 5; When increasing the axial length L1 of the bobbin 5, the outer side of the outer hook 2 (direction of arrow F in FIG. 5)
If the sewing needle 9 is extended, the tip of the sewing needle 9 comes into contact with the bobbin 5, so that it cannot be extended to the outside of the outer hook 2 unnecessarily. Also, as shown in Fig. 7, the inner side of the outer hook 2 (opposite to the direction of arrow F)
When the inner pot 3 is extended, the bottom portion 7 of the inner pot 3 becomes deeper as shown by the imaginary line 7a. When sewing is performed using such an inner hook 3, the needle thread loop 8a slides along the outer circumferential surface of the bottom 7a of the inner hook 3a, and the needle thread loop 8a touches the bottom 7a.
It gets caught near the lower end 7b. Therefore, in synchronization with the vertical movement of the sewing needle 9, the upper thread loop 8a
can slide along the outer circumferential surface of the bottom portion 7a of the inner hook 3a, causing trouble in sewing work.

In order to solve this problem, it may be possible to perform sewing using a vertical full-rotation hook with a larger outer diameter, but in this case, in order to increase the sewing speed as much as possible, it is necessary to rotate the outer hook at high speed. In this case, frictional heat is generated due to sliding contact between the raceway of the outer rotor and the raceway of the inner rotor that fits into the raceway, resulting in seizure between the outer rotor and the inner rotor. Therefore, the rotational speed of the outer hook cannot be increased unnecessarily.

Problems to be Solved by the Invention Therefore, an object of the present invention is to increase the amount of bobbin thread wound around the bobbin without increasing the outer diameter of the hook and without hindering the movement of the needle. The purpose of the present invention is to provide a vertical full-rotation hook that can be rotated in a vertical direction.

Means for Solving the Problems In the present invention, a raceway 30 is formed on the inner peripheral surface of the outer rotor 23, and a raceway 33 formed on the outer peripheral surface of the inner rotor 24 is fitted into the raceway 30 so that the outer rotor 24 can be externally The rotary hook 23 is rotationally driven, and the rail 33 and the track groove 30 are in a plane perpendicular to the rotational axis l1 of the outer hook 23. needle 38
The free end of the bobbin 26 closest to the needle 38
There is also a vertical full-rotation hook characterized by being inclined with respect to the rotation axis l1 of the outer hook 23 in a direction away from the movement path of the outer hook 23.

Effect According to the present invention, the axis of the bobbin 26 in the inner hook 24 is set such that the free end of the bobbin 26 closest to the needle 38 moves away from the movement path of the needle 38.
It is inclined with respect to the rotational axis l1 of the outer hook 23.
This eliminates the need to increase the radius of the bobbin 26, and therefore increases the axial length of the bobbin 26 without increasing the outer diameter of the outer hook 23 to increase the winding amount of the bobbin thread. can do.
Therefore, the outer hook 23 is rotated at high speed without unnecessarily increasing the circumferential speed of the outer hook 23, and the needle 38 that reciprocates in synchronization with the rotational movement of the outer hook 23 is used to achieve high speed operation. Can perform sewing operations.

Moreover, since the circumferential speed of the outer hook 23 does not increase unnecessarily, the raceway 30 of the outer hook 23 and the rail 33 of the inner hook 24 that fit into the raceway 30
It is possible to suppress the rise in temperature due to the sliding contact with the metal, and thereby to prevent seizure. Furthermore, since the axis of the bobbin 26 is tilted, the inner hook 24 is tilted.
The upper thread can be smoothly slid on the outer circumferential surface of the bottom of the inner hook 24, and the thread passing operation can be easily performed. This makes it possible to perform the thread crossing operation without applying unnecessarily large tension to the upper thread, preventing the occurrence of thread clumps and looping, and forming high-quality stitches. .

Embodiment FIG. 1 is a perspective view of a vertical full-rotation hook 20 showing one embodiment of the present invention, FIG. 2 is a sectional view thereof, and FIG. 3 is a perspective view of a bobbin 26. The vertical full-rotation hook 20 includes an outer hook 23 fixed to a drive shaft 21 with a set screw 22, an inner hook 24 housed in the outer hook 23, and a bobbin 26 on which a bobbin thread 25 is wound. and a bobbin case 27 fitted into the inner hook 24.

The bobbin 26 has a pair of left and right flanges 36a, 3
6b, and a shaft portion 35 around which the bobbin thread 25 is wound. The outer hook 23 has a tip 29 that allows the upper thread 28 to slide along the outer peripheral surface of the inner hook 24.
3 has a track groove 30 formed in a plane perpendicular to the rotational axis l1.

The inner hook 24 is formed with a recess 32 into which an inner hook rotation preventing member 31 fixed to a base (not shown) of the sewing machine body is fitted to prevent rotation of the inner hook 24. Furthermore, a rail 33 that fits into the rail groove 30 is formed on the outer circumferential surface of the inner hook 24 . The upper thread 28 is fitted into the rail 33 in a direction intersecting the extending direction of the rail 33, and the upper thread 28 is inserted into the rail 33 in order to form an upper thread loop 28a (described later) with the tip 29 of the outer hook 23. A thread cutting groove 34 is formed to partially fix the passing path of the thread 28. Such an inner pot 24 has its axis l
2 is housed in the outer hook 23 forming a predetermined angle A with respect to the rotation axis l1 of the outer hook 23. This angle A is selected to be an angle (for example, 8 degrees or more) at which the sewing needle 38 does not come into contact with the flange 36a of the bobbin 26 even when it reaches its lowest position S.

FIG. 4 is a side view of the inner hook 24 for explaining the sliding movement of the upper thread 28. Referring also to FIGS. 1 to 3, as described above, the vertical full rotation hook 20
The bobbin 26 is housed in a bobbin case 27 with the bobbin thread 25 wound thereon. Furthermore, this bobbin case 27 is fitted into the inner hook 24 along the axis l2 direction, and is inserted into a recess 32 formed in the inner hook 24.
An inner rotary locking member 31 is fitted therein.

When performing sewing work using a lockstitch sewing machine equipped with such a vertical full-rotation hook 20, the outer hook 23
The sewing needle 38 is suspended near the flange 36a of the bobbin 26 in synchronization with the rotational movement of the flange 36a, and moves to the lowest position S without contacting the flange 36a. At almost the same time, the needle thread 28 is moved by the tip 29 of the outer hook 23.
A part of the is attached. Further, as shown in FIG. 4, the other part of the needle thread 28 fits into the thread cutting groove 34 of the rail 33, and becomes the proximal end of the needle thread loop 28a. As the rotation of the outer hook 23 progresses,
As shown in FIG. 4, the loop shape of the needle thread loop 28a is enlarged, and a portion thereof comes into sliding contact with the outer peripheral surface of the lower portion 24b of the bottom portion 24a of the inner hook 24. Furthermore, as shown in FIG. 4,
The needle thread loop 28a is attached to the lower portion 24 of the bottom portion 24a.
b is not formed on the drive shaft 21 side as shown by the imaginary line C (see FIG. 2), the needle thread loop 28a is pulled near the lower portion 24b of the bottom portion 24a from the state shown in FIG. Inner pot 24 without hanging
Smoothly slides around the outer circumferential surface of the Further, as the outer hook 23 rotates, the upper thread 28 returns to the state shown in FIG. 4, and this series of sliding movements of the upper thread loop 28a are performed continuously.
Therefore, since no undesired tensile force is applied to the needle thread 28, the sewing operation can be performed without the needle thread 28 being cut during sewing.

In the conventional vertical full-rotation hook 1, the axial length L1 of the bobbin 5 is 9 mm, and the amount of bobbin thread wound around the bobbin 5 is, for example, 40 m with 50# cotton thread.
It was moderately hot. However, in the vertical full-rotation hook 20 of the present invention, for example, if the axial length L2 of the bobbin 26 is set to 14 mm, the amount of winding of the bobbin thread is increased to about 60 m. In other words, the amount of sewing that can be done with one bobbin is increased by 1.5 times compared to the conventional sewing machine, thereby reducing the number of times the sewing operation is stopped to replace the bobbin, thereby improving sewing efficiency.

Effects of the Invention As described above, according to the present invention, the amount of winding of the bobbin thread wound around the bobbin is increased, and therefore the axial length of the bobbin can be increased without interfering with the movement of the sewing needle. This makes it possible to significantly improve sewing performance.

[Brief explanation of drawings]

1 is a perspective view of a vertical full-rotation hook 20 showing one embodiment of the present invention, FIG. 2 is a sectional view of the vertical full-rotation hook 20 shown in FIG. 1, FIG. 3 is a perspective view of a bobbin 26, and FIG. 5 is a sectional view of the conventional vertical full-rotation hook 1, FIG. 6 is a perspective view of the bobbin 5, and FIG. 7 is a diagram for explaining the sliding movement of the upper thread 28. It is a side view of the inner pot 3 housed in the. 20... Vertical full rotation hook, 21... Drive shaft, 2
2... Set screw, 23... Outer hook, 24... Inner hook, 25... Lower thread, 26... Bobbin, 27... Bobbin case, 28... Upper thread, 29... Tip, 30
...Race groove, 31...Inner hook rotation stopper member, 32...
...Recess, 33...Rail, 34...Thread cutting groove, 35
...Shaft portion, 36a, 36b...Flange, 38...
...Sewing needle, l1...rotation axis, l2...axis.

Claims (1)

[Claims] 1. A raceway groove 30 is formed on the inner peripheral surface of the outer hook 23,
A rail 33 formed on the outer peripheral surface of the inner hook 24 is fitted into this rail groove 30, and the outer hook 23 is rotationally driven. In the vertical full-rotation hook, which is located inside the inner hook 24, the axis of the bobbin 26 inside the inner hook 24 is aligned with the needle 38.
The free end of the bobbin 26 closest to the needle 38
The vertical full-rotation hook is inclined with respect to the rotational axis l1 of the outer hook 23 in a direction away from the movement path of the outer hook 23.