JP2002210282A - Rotary shuttle device for sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an external diameter of a rotary shuttle device for a sewing machine without reducing an amount of a bobbin thread wound around a bobbin. SOLUTION: In this rotary shuttle device 5, a thread tension spring 10 pressing the bobbin thread 20 drawn out from the bobbin is installed to an outer side face A of an end face part of a bobbin housing cap 9. Thereby, because the thread tension spring 10 is absent between the peripheral face of the bobbin housing cap 9 and the inner circumferential face of a shuttle body 7, it is unnecessary to form a gap for setting the thread tension spring 10 between the peripheral face of the bobbin housing cap 9 and the inner circumferential face of the shuttle body 7. Accordingly, the external diameter of the rotary shuttle device 5 can be reduced without miniaturizing the bobbin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rotary hook device for a sewing machine.

[0002]

2. Description of the Related Art In general, a post-type sewing machine having a cylindrical post portion provided on a sewing machine bed is used for sewing a bag portion such as a bag or a shoe having a curve with a small radius. The post unit accommodates a rotary hook device provided with an outer hook that is driven to rotate about a vertical axis.

[0003] This rotary hook device includes an outer hook, an inner hook, a bobbin,
It is composed of a bobbin storage cap, a thread tension spring, and the like. An inner pot is rotatably held in the outer pot, a bobbin is stored in the inner pot, and a bobbin storage cap for storing the bobbin is attached to the inner pot. The thread tension spring is a plate-shaped spring that presses the bobbin thread pulled out of the bobbin, and is attached to the outer peripheral surface of the bobbin storage cap. For this reason, between the outer peripheral surface of the bobbin storage cap and the inner peripheral surface of the inner hook, a ring-shaped space for locating the thread tension spring must be secured.

[0004] In the case of sewing a bag portion such as a bag or shoes, the smaller the diameter of the post portion is, the easier it is to sew a curved portion having a smaller radius.

Therefore, in a post-type sewing machine,
There is a demand to make the diameter of the post as small as possible.

[0006]

The diameter of the post portion depends on the diameter of the outer hook (the outer diameter of the rotary hook device). To reduce the diameter of the post portion, the outer diameter of the rotary hook device must be reduced. It is possible to do.

However, when the outer diameter of the rotary hook device is simply reduced, the diameter of the inner hook and the bobbin stored in the inner hook also decreases, and the amount of the lower thread wound on the bobbin decreases. Become. When the amount of bobbin thread wound on the bobbin decreases, the frequency of replenishing the bobbin thread increases, and the sewing operation must be interrupted each time the bobbin thread is replenished, resulting in a reduction in the working efficiency of the sewing operation.

[0008] In addition to the post type sewing machine, if the outer diameter of the rotary hook device is reduced, the size of the sewing machine using the rotary hook device can be reduced accordingly.

An object of the present invention is to provide a rotary hook device of a sewing machine that can reduce the outer diameter without reducing the amount of bobbin thread wound on a bobbin.

[0010]

According to the first aspect of the present invention,
A storage chamber for storing a bobbin storage cap for storing a bobbin is formed in an inner peripheral portion and a rail is formed in an outer peripheral portion, and a rail groove in which the rail is fitted is formed in an inner peripheral portion. In a rotary hook device of a sewing machine having an outer hook that is driven to rotate around a center, a thread tension spring that presses a lower thread pulled out from the bobbin is attached to an outer surface of an end face portion of the bobbin storage cap.

Therefore, there is no thread tension spring between the outer peripheral surface of the bobbin storage cap and the inner peripheral surface of the inner hook, and there is no thread tension spring between the outer peripheral surface of the bobbin storage cap and the inner peripheral surface of the inner shuttle. There is no need to secure a ring-shaped space for positioning the inner bobbin and the inner diameter of the inner hook without reducing the outer diameter of the bobbin and the bobbin storage cap. The outer diameter of the rotary hook device can be reduced without reducing the amount of yarn.

According to a second aspect of the present invention, in the rotary hook device of the sewing machine according to the first aspect of the present invention, the inner hook retainer which is attached to the outer hook and forms a part of the track groove has a sectional shape of U. It is formed in the shape of a letter.

Therefore, by making the shape of the inner hook retainer a U-shaped cross section, the strength can be maintained even if the thickness of the inner hook retainer is reduced, and the thickness of the inner hook retainer is reduced. Thus, the outer diameter of the rotary hook device can be further reduced.

According to a third aspect of the present invention, in the rotary hook device for a sewing machine according to the first or second aspect, a portion of the outer surface of the end surface of the bobbin storage cap which is covered with the thread tension spring is provided. A recess is formed at a position intersecting with the path of the lower thread pressed by the spring.

Therefore, the lower thread pressed by the thread tension spring and passing over the concave portion is strongly pressed by the thread tension spring at the edge of the concave portion, whereby the lower thread crosses the concave portion. From being out of position,
The bobbin thread can be reliably held down by the thread tension spring.

[0016]

FIG. 1 shows a first embodiment of the present invention.
A description will be given with reference to FIG. FIG. 1 is a front view showing a post-type sewing machine, FIG. 2 is a plan view of a rotary hook device used in the post-type sewing machine, and FIG. 3 shows a guide groove formed in a bobbin storage cap which is a part of the rotary hook device. FIG. 4 is a front view showing the rotary hook device, and FIG. 5 is a longitudinal sectional front view showing the rotary hook device.

In a post-type sewing machine, a sewing machine main body 2 having a sewing needle 1 reciprocating vertically is attached to a sewing machine bed 3. Further, a post section 4 is provided upright on the sewing machine bed 3 at a position facing the sewing machine needle 1.

The post portion 4 is a hollow cylindrical member, and a needle plate (not shown) having a needle hole (not shown) into which the sewing needle 1 is inserted is provided at the upper end thereof. . Also,
The rotary hook device 5 is housed inside the post portion 4. This rotary hook device 5 includes an outer hook 6, an inner hook 7, a bobbin 8,
It is composed of a bobbin storage cap 9, a thread tension spring 10, and the like.

The outer pot 6 has a storage chamber 11 for storing the inner pot 7.
A fitting shaft 12 fitted to a rotation drive shaft (not shown) extending in the vertical direction; a sword tip 13 for hooking a loop portion of the upper thread with a rotation operation; Are formed. A part of the rail groove 14 is formed by a U-shaped groove formed in an inner peripheral portion of a peripheral wall of the outer hook 6 (a right side portion in FIG. 5), and another part of the outer hook 6 is formed. It is formed by a groove having an L-shaped cross section formed on the inner periphery of the peripheral wall, and an inner hook retainer 15 screwed to the outer periphery of the outer hook 6 so as to cover the groove. The inner hook retainer 15 is formed in a U-shape in cross section, and has a small thickness. A sword protection spring 1 is provided on the outer periphery of the outer hook 6.
6 is screwed.

A ring-shaped rail 17 is formed on the outer periphery of the inner hook 7 so as to be fitted into the rail groove 14, and a storage chamber 18 is formed on the inner periphery. A stud 19 is provided upright at the center of the inner pot 7, and the bobbin 8 is rotatably attached to the stud 19. A bobbin thread 20 is wound around the bobbin 8.

The bobbin storage cap 9 is a member that stores the bobbin 8 and is stored together with the bobbin 8 in the storage chamber 18 of the inner hook 7, and is attached to a stud 19. A ring-shaped protrusion 21 is formed on the outer peripheral side of the end surface outer surface A of the bobbin storage cap 9, and a concave portion 22 is formed inside the protrusion 21. In this recess 22,
A thread tension spring 10 for holding a lower thread 20 pulled out from the bobbin 8 is attached.

The thread tension spring 10 is formed in a crescent shape. One end of the thread tension spring 10 is fixed by a set screw 23. The thread tension spring 10 has a substantially central portion for adjusting the pressing force when the thread tension spring 10 presses the bobbin thread 20. The pressing force adjusting screw 24 is attached. In the thread tension spring 10, an arc-shaped outer peripheral portion is opposed to an inner peripheral portion of a protruding portion 21 formed with substantially the same curvature with a small gap. Further, a recess 25 is formed in a portion of the recess 22 that is covered by the thread tension spring 10 and intersects with the path of the lower thread 20 pressed by the thread tension spring 10.

The bobbin thread 20 pulled out of the bobbin 8 is guided to the outer peripheral side of the bobbin storage cap 9 through a slit groove (not shown) formed in the peripheral wall 26 of the bobbin storage cap 9, and then the protrusion 21 Guide groove 27 formed in
Is led to the recess 22 side, and is guided to the lower side of the thread tension spring 10. The protruding portion 21 is in an overhang state with respect to the guide groove 27 (see FIG. 3).
The lower thread 20 passed through the guide groove 27 does not easily come off the guide groove 27.

In such a configuration, in the rotary hook device 5, the thread tension spring 10 for pressing the bobbin thread 20 pulled out from the bobbin 8 is provided on the outer surface A of the end face portion of the bobbin storage cap 9.
Since there is no need to secure a ring-shaped space for positioning the thread tension spring 10 between the outer peripheral surface of the peripheral wall portion 26 of the bobbin storage cap 9 and the inner peripheral surface of the inner shuttle 7, The inner diameter of the inner hook 7 and the outer diameter of the outer hook 6, that is, the outer diameter of the rotary hook device 5, can be reduced while maintaining the outer diameter of the bobbin 8 as before. Further, since the bobbin 8 can be maintained at the same size as the conventional one, the bobbin 8 can be maintained as before without reducing the amount of the lower thread 20 wound on the bobbin 8.

For this reason, if this rotary hook device 5 having a reduced outer diameter is used with a post-type sewing machine, the diameter of the post portion 4 can be reduced, and sewing of bags such as bags and shoes can be performed. In such a case, the sewing operation of a curved portion having a small radius can be easily performed.

Moreover, since the bobbin 8 can be maintained in the same amount as the bobbin thread 20 wound on the bobbin 8 without being downsized, the sewing operation can be performed without increasing the frequency of the sewing operation accompanying the replenishment of the bobbin thread 20. The work efficiency of the work can be maintained as before.

Further, in the present embodiment, the inner hook retainer 15 has a U-shaped cross section, so that the strength can be maintained even if the inner hook retainer 15 is thinned. By reducing the thickness of the inner hook retainer 15, the outer diameter of the rotary hook device 5 can be further reduced, and the diameter of the post portion 4 can be further reduced.

After the bobbin 8 is pulled out from the bobbin 8 and guided to a position where the bobbin 8 is pressed by the thread tension spring 10, the bobbin thread 20 passes through a guide groove 27 formed in the projecting portion 21.
The lower thread 20 pulled out from the thread can be stably guided to a position where the lower thread 20 is pressed by the thread tension spring 10.

The recess 22 of the bobbin housing cap 9 is a portion covered by the thread tension spring 10
Since the recess 25 is formed at a position intersecting with the path of the lower thread 20 held down by the thread tension spring 10, the lower thread 20 pressed by the thread tension spring 10 and passing over the recess 25 is formed by the recess 2.
5 is strongly pressed by the thread tension spring 10 at the edge, thereby preventing the lower thread 20 from coming off from a position intersecting with the recess 25, and reliably pressing the lower thread 20 by the thread tension spring 10. I can do it.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. 1 to 5
The same reference numerals are used for the same parts as those described in, and the description is omitted. FIG. 6 is a plan view showing the rotary hook device of the present embodiment, FIG. 7 is a vertical sectional front view thereof, and FIG. 8 is a perspective view showing a bobbin storage cap.

The basic structure of the rotary hook device 5a of the present embodiment is the same as that of the first embodiment.
It comprises a bobbin 8, a bobbin storage cap 9a, a thread tension spring 10, and the like. The bobbin storage cap 9a of the present embodiment has a slit groove 28 for guiding the lower thread 20 pulled out from the bobbin 8 to the outer peripheral portion of the bobbin storage cap 9a.
A return hole 29 for returning the bobbin thread 20 to the inner peripheral side of the bobbin storage cap 9a again; a guide groove 30 formed in the inner surface of the end face of the bobbin storage cap 9a; and a thread tension spring communicating with the guide groove 30. Communication hole 3 opening in the part covered by 10
1 are formed.

The bobbin thread 20 pulled out of the bobbin 8 is guided to the outer peripheral side of the bobbin storage cap 9a through the slit groove 28 as shown in FIG. Returned to the guide groove 30
After the thread tension spring 10 is guided through the communication hole 31
It is pulled out to the position where it is held down.

With this configuration, in the rotary hook device 5a of the present embodiment, similarly to the rotary hook device 5 of the first embodiment, the thread tension spring 10 for pressing the lower thread 20 pulled out from the bobbin 8 is provided. Is attached to the end face outer surface A of the bobbin storage cap 9a.
a between the peripheral wall portion 26a and the inner peripheral surface of the inner hook 7
There is no need to secure a ring-shaped space for locating 0, and the outer diameter of the rotary hook device 5a can be reduced without reducing the outer diameter of the bobbin 8. And the amount of the lower thread 20 wound on the bobbin 8 can be maintained as before.

For this reason, if the rotary hook device 5a having a reduced outer diameter is used with a post type sewing machine, the post portion 4
(See FIG. 1), the diameter of the bag can be reduced, and the sewing operation of a curved portion with a small radius can be easily performed when performing the sewing operation of a bag portion such as a bag or shoes.

Further, the bobbin 8 can be maintained in the same amount as the bobbin thread 20 wound on the bobbin 8 without being downsized, so that the frequency of replenishment of the bobbin thread 20 is not increased and the work efficiency of the sewing operation is reduced. It can be maintained as before.

In the present embodiment, the lower thread 20 guided to the position where the thread is pulled out from the bobbin 8 and pressed by the thread tension spring 10 is connected to the slit groove 28, the hole 29, the guide groove 30, and the communication hole. Since the lower thread 31 is passed through the bobbin 8, the lower thread 20 pulled out from the bobbin 8 can be stably guided to a position where the lower thread 20 is pressed by the thread tension spring 10.

[0037]

According to the rotary hook device of the sewing machine according to the first aspect of the present invention, the thread tension spring for holding the bobbin thread pulled out from the bobbin is attached to the outer surface of the end surface of the bobbin storage cap. A ring for positioning the thread tension spring between the outer peripheral surface of the bobbin storage cap and the inner peripheral surface of the inner hook, since there is no thread tension spring between the outer peripheral surface of the storage cap and the inner peripheral surface of the inner hook. There is no need to secure a space in the shape of the inner bobbin, so that the inner diameter of the inner hook can be reduced without reducing the outer diameter of the bobbin and the bobbin storage cap, and the amount of bobbin thread wound on the bobbin is reduced. And the outer diameter of the rotary hook device can be reduced.

According to the second aspect of the present invention, in the rotary hook device of the sewing machine according to the first aspect of the present invention, the inner hook retainer which is attached to the outer hook and forms a part of the track groove has a U-shaped cross section. Since the inner hook retainer has a U-shaped cross section, the strength can be maintained even if the thickness of the inner hook retainer is reduced. By reducing the thickness, the outer diameter of the rotary hook device can be further reduced.

According to a third aspect of the present invention, in the rotary hook device for a sewing machine according to the first or second aspect, a portion of the bobbin storage cap which is covered with the thread tension spring on an outer end face of the bobbin storage cap is provided. Since the concave portion is formed at a position intersecting the passage of the lower thread held by the spring, the lower thread pressed by the thread tension spring and passing over the concave portion has a thread tension spring at the edge of the concave portion. As a result, the lower thread can be prevented from coming off from the position crossing the concave portion, and the lower thread can be reliably pressed by the thread tension spring.

[Brief description of the drawings]

FIG. 1 is a front view showing a post-type sewing machine according to a first embodiment of the present invention.

FIG. 2 is a plan view of a rotary hook device used in the post-type sewing machine.

FIG. 3 is a side view showing a guide groove formed in a bobbin storage cap which is a part of the rotary hook device.

FIG. 4 is a front view showing the rotary hook device.

FIG. 5 is a vertical sectional front view showing the rotary hook device.

FIG. 6 is a plan view showing a rotary hook device according to a second embodiment of the present invention.

FIG. 7 is a longitudinal sectional front view thereof.

FIG. 8 is a perspective view showing a bobbin storage cap.

[Explanation of symbols]

 Reference Signs List 6 outer hook 7 inner hook 8 bobbin 9, 9a bobbin storage cap 10 thread tension spring 14 track groove 15 inner hook retainer 17 rail 18 storage chamber 20 bobbin thread 25 recessed part A end face outer surface

Claims (3)

[Claims] 1. An inner pot in which a storage chamber for storing a bobbin storage cap for storing a bobbin is formed in an inner peripheral portion and a rail is formed in an outer peripheral portion, and a rail groove in which the rail is fitted is formed in an inner peripheral portion. A bobbin tensioner spring for holding a bobbin thread pulled out from the bobbin is attached to an outer surface of an end face portion of the bobbin storage cap. A rotary hook device for a sewing machine. 2. The rotary hook of a sewing machine according to claim 1, wherein an inner hook retainer attached to the outer hook and forming a part of the rail groove is formed in a U-shaped cross section. apparatus. 3. A concave portion is formed at a portion of the outer surface of the end face portion of the bobbin storage cap which is covered with the thread tension spring and intersects with a path of a lower thread pressed by the thread tension spring. 3. The rotary hook device for a sewing machine according to claim 1, wherein