JP2002191888A - Dp shuttle for sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DP shuttle for a sewing machine, by which a gap where an needle thread passes through (a thread disposing groove) between a rotating hook bobbin case holder lace thread disposing part and a rotating hook section can be widened without reducing the thread amount of a bobbin. SOLUTION: The DP shuttle is provided with a rotating hook 2 having a core point 2c for caching a needle thread loop, with a rotating hook bobbin case holder 4 having a needle thread introducing end 4b1, a needle thread deriving end 4b2 and the rotating hook bobbin case holder lace thread disposing part 4b which is formed in a circular arcuate shape between the introducing and deriving ends 4b1 and 4b2, with a bobbin case 6 supported by the rotating hook bobbin case holder 4 and with a thread disposing groove 16 formed between the rotating hook 2 and the rotating hook bobbin case holder lace thread disposing part. The needle thread loop caught by the core point 2c passes through the rotating hook bobbin case holder 4 and the bobbin case 6 by way of the thread disposing groove in the DP shuttle. In the DP shuttle, the radial center of a circular arc in the rotating hook bobbin case holder lace thread disposing part is deviated to a side far from the lace thread disposing part concerning the center of the rotating hook bobbin case holder 4c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical rotation rotary hook of a sewing machine, and more particularly to an improvement in the shape of an inner hook and a bobbin case of a DP hook of a sewing machine.

[0002]

2. Description of the Related Art A conventional DP hook (a hook in which the point of the outer hook is located between the needle drop position and the lower needle thread take-out point of the bobbin).
As shown in FIGS. 7 to 9, an outer hook 2, an inner hook 4 supported by the outer hook 2, and a bobbin case 6 supported by the inner hook 4. A back plate 2a and an inner hook retainer 2b are fixed to the outer hook 2, respectively.

[0003] The inner hook 4 is provided with a lace portion 4a on the circumference thereof, and the lace portion 4a is fitted into a race groove 2d of the outer hook 2. The lace portion 4a is partially cut away to form an inner hook lace yarn transfer portion 4b. The left and right ends of the inner hook race yarn transfer section 4b are a needle thread introduction end 4b1 and a needle thread lead-out end 4b.
It is 2. The lace thread transfer part 4b is located at the center 4 of the inner pot 4.
It is formed by an arc of radius R1 centered at c. Therefore, the distance L1 from the inner hook center 4c to the needle thread introduction end 4b1
And the distance L2 from the inner hook center 4c to the needle thread lead-out end 4b2.
Is R1. R1 is smaller than the outer radius of the race portion 4a.

[0004] Inner hook race yarn transfer section 4b of bobbin case 6
6a also has the same shape as the inner hook race yarn transfer section 4b. That is, the outer periphery of the portion 6a corresponding to the inner hook race yarn transfer section 4b is formed by an arc having a radius R1 about the center 4c of the inner hook 4.

[0005] As shown in Figs.
The lace yarn transfer portion 4b is fixed so as to be located above. When the sewing object 10 is placed on the needle plate 8 and the main shaft (not shown) is rotated, the needle thread 14 captured by the blade point 2c is moved by the vertical movement of the needle 12 and the rotation of the outer hook 2 in the direction A.
Rotates around the inner hook 4 and the bobbin case 6, but at this time, the needle thread 14 passes through the gap 16 between the inner hook 4 and the inner hook presser 2b of the outer hook 2, and passes through the inner hook race thread transfer portion 4b. It moves from the side of the needle thread introduction end 4b1 to the side of the needle thread exit end 4b2 while contacting with the needle thread.

[0006]

Due to the structure of the DP hook, the thickness 6D of the bobbin case 6 cannot be increased. Therefore, the bobbin case 6 is accommodated in the bobbin by increasing the diameter as much as possible in the radial direction. Is increasing. Therefore, a gap (thread transfer groove) 16 through which the needle thread 14 passes between the inner hook race thread transfer section 4b and the outer hook 2 (the inner hook presser 2b) becomes narrow (for example, about 0.6 mm), and the needle thread 14 Since the bending resistance of the thread becomes large, the phenomenon that the thread does not pass smoothly with a thick thread or a thread having a large frictional resistance occurs, and sometimes a sewing failure such as thread breakage or looping may occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sewing machine capable of widening a gap (thread transfer groove) through which a needle thread passes between an inner hook race thread transfer section and an inner hook retainer without reducing the amount of bobbin thread. To provide a DP pot.

[0008]

According to the present invention, there is provided, in accordance with the present invention, an outer hook having a sword point for catching a needle thread loop, a needle thread introduction end and a needle thread lead-out end, and a needle thread. An inner hook having an inner hook race thread transfer section formed in an arc shape between the introduction end and the needle thread output end, a bobbin case supported by the inner hook, and the outer hook and the inner hook race thread transfer section. A thread transfer groove formed between the inner hook race and the bobbin case, wherein the needle thread loop captured by the blade passes through the inner transfer hook and the bobbin case. The DP center of the sewing machine is provided in which the center of the radius is deviated to the side far from the lace thread transfer portion with respect to the center of the inner hook.

For example, the distance between the needle thread introduction end and the center of the inner hook is made the same as the distance between the needle thread lead-out end and the center of the inner hook, and the radius of the arc of the inner hook race thread transfer portion is set to The distance between the needle thread introduction end and the needle thread exit end and the center of the inner hook can be made larger.

Alternatively, the distance between the needle thread introduction end and the center of the inner hook is shorter than the distance between the needle thread lead-out end and the center of the inner hook, and the radius of the arc of the inner hook race thread transfer portion is reduced. The distance between the needle thread lead-out end and the center of the inner hook can be made larger.

Preferably, the outer periphery of a portion of the bobbin case corresponding to the inner hook race yarn transfer portion has the same shape as the inner hook race yarn transfer portion.

Alternatively, the outer periphery of a portion of the bobbin case corresponding to the inner hook race yarn transfer portion may be formed in an arc centered on the inner hook center so as not to extend from the inner hook race yarn transfer portion. .

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the P hook will be described.

FIGS. 1 to 3 show a DP hook according to a first embodiment. This DP hook has an outer hook 2 and an outer hook 2 as in the conventional example.
, An inner hook retainer 2b also fixed to the outer hook 2, an inner hook 4 supported by the outer hook 2, and a bobbin case 6 supported by the inner hook 4. The inner hook 4 is provided with a race portion 4a made of a synthetic resin on a circumferential portion thereof, and the race portion 4a is fitted into a race groove 2d of the outer hook 2. The lace part 4a is partially cut away and the inner hook lace yarn transfer part 4b
Is formed. The lace thread transfer section 4b has a needle thread introduction end 4b1 and a needle thread exit end 4b2 at both ends. In addition, the lace yarn crossing portion 4b may be made of steel, but if it is made of synthetic resin, it can be easily formed, so that it is suitable for application of the present invention.

In the present embodiment, the shape of the arc of the race thread transfer portion 4b of the inner hook 4 and the shape of the outer shape of the portion 6a of the bobbin case 6 corresponding to the race yarn transfer portion 4b are different from the conventional example. That is, the positions of the needle thread introduction end 4b1 and the needle thread lead-out end 4b2 of the inner hook race yarn transfer section 4b are the same as those in the conventional example, and the distance between each position and the inner hook center 4c is L1 and L2 ( Assuming that the radius of the arc of the race yarn transfer portion 4b according to the conventional example is R1, L1 = L2 = R1), but the center of the arc of the race yarn transfer portion 4b is the inner hook center 4c.
, It is deviated to the side (the lower side in the figure) far from the inner hook race yarn transfer portion 4b. Therefore, if the radius of the arc of the race yarn transfer portion 4b according to the present embodiment is R2, R2> L
1 = L2 = R1. The outer periphery of a portion 6a of the bobbin case 6 corresponding to the inner hook race transfer portion 4b is also formed to have the same arc as the race yarn transfer portion 4b.

According to the present embodiment, the gap (thread transfer groove) through which the needle thread passes between the inner hook race thread transfer portion 4b and the inner hook presser 2b without reducing the radial size of the bobbin case 6. 16 can be made larger than a conventional shuttle.
Therefore, the bending resistance of the needle thread is reduced, the inside and the inside of the needle thread can be smoothly transferred, and thread breakage and looping can be prevented.

FIGS. 4 and 5 show a DP shuttle according to a second embodiment. This DP hook differs from the first embodiment in that
The distance L3 from the inner hook center 4c to the needle thread introduction end 4b1 of the inner hook race thread transfer portion 4b is made shorter than before, and the inner hook center 4c
The distance L4 from the inner thread to the needle thread lead-out end 4b2 is R1 as in the conventional example, and the center of the arc of the inner hook race thread transfer section 4b is farther from the inner hook race thread transfer section 4b than the inner hook center 4c (see FIG. Below). If the radius of the arc of the race yarn transfer portion 4b according to the present embodiment is R3, then R3>L4> L3 = R1. Also, the outer periphery of the portion 6a of the bobbin case 6 corresponding to the race yarn transfer portion 4b has a shape having the same arc as the race yarn transfer portion 4b.

According to the present embodiment, similarly to the first embodiment, the yarn between the inner hook race yarn transfer section 4b and the inner hook presser 2b can be formed without reducing the radial size of the bobbin case 6. The gap 16 through which the thread can pass can be made larger than that of the conventional shuttle, so that the yarn transfer can be performed smoothly. Furthermore, in the case of the present embodiment, the gap 16 on the side of the needle thread introduction end 4b1 is widened, so that sewing failure due to biting or the like at the time of introduction of the needle thread is prevented.

FIG. 6 shows a DP hook according to a third embodiment. Since the inner hook 4 of this DP hook has the same structure as that of the second embodiment, its explanation is omitted. The outer periphery of the portion 6a of the bobbin case 6 corresponding to the inner hook race thread transfer section 4b has a size such that the inner circumference of the inner hook center 4c (bobbin It is also the center of the case 6).

According to this embodiment, in addition to the same effects as in the second embodiment, the center of the outer shape of the portion 6a corresponding to the inner hook race thread transfer portion 4b of the bobbin case 6 is the center of the bobbin case 6. Therefore, the forming process is facilitated, and there is an effect of cost reduction.

Although the present invention has been described based on the embodiments shown in the drawings, the present invention is not limited to these embodiments, and can be variously modified. For example, although the inner hook 4 of the third embodiment has the same structure as the second embodiment, it has the same structure as the inner hook of the first embodiment, and corresponds to the inner hook race yarn transfer section 4b. The outer periphery of the portion 6a of the bobbin case 6 can be formed in an arc shape having a size such that the outer periphery of the portion 6a does not protrude from the shape of the inner hook race thread transfer portion 4b and has a center at the inner hook center 4c.

[0022]

According to the present invention, an outer hook having a point for capturing a needle thread loop, a needle thread introduction end and a needle thread exit end, and a circle between the needle thread introduction end and the needle thread exit end. An inner hook having an inner hook race yarn transfer portion formed in an arc shape, a bobbin case supported by the inner hook, and a yarn transfer groove formed between the outer hook and the inner hook race yarn transfer portion, In the DP hook, in which the needle thread loop captured at the point of the sword passes through the inner hook and the bobbin case through the thread transfer groove, the center of the radius of the arc of the inner hook race thread transfer section is moved from the lace thread transfer section to the inner hook center. By deviating to the far side, the yarn transfer groove can be made wider than before, the bending resistance of the yarn can be reduced, the yarn transfer can be realized smoothly, and yarn breakage and looping can be prevented.

The distance between the needle thread introduction end and the center of the inner hook is made the same as the distance between the needle thread lead-out end and the center of the inner hook, and the radius of the arc of the inner hook race yarn transfer section is adjusted to the needle thread introduction end. And when it is larger than the distance between the needle thread lead-out end and the center of the inner hook, the thread transfer groove becomes wider than before, so the bending resistance of the thread decreases,
Smooth yarn transfer can be realized, and yarn breakage and looping can be prevented.

The distance between the needle thread introduction end and the center of the inner hook is shorter than the distance between the needle thread lead-out end and the center of the inner hook. If the distance is larger than the distance between the inner hook and the center of the inner pot, the thread transfer groove is wider than before, reducing the bending resistance of the thread, realizing smooth thread transfer and preventing thread breakage and looping. can do. Furthermore, since the thread transfer groove on the needle thread introduction end side becomes wider,
Sewing failure due to biting or the like when introducing the needle thread is prevented.

When the outer periphery of the portion corresponding to the inner hook race yarn transfer portion of the bobbin case is formed in the same shape as the inner hook race yarn transfer portion, the bobbin is not reduced in radial size as compared with the conventional example. In addition, the thread transfer groove can be made wider than before. Therefore, it is possible to reduce the bending resistance of the yarn without reducing the amount of the lower yarn, realize smooth yarn transfer, and prevent yarn breakage and looping.

When the outer periphery of the portion corresponding to the inner hook race yarn transfer portion of the bobbin case is formed by an arc centered on the inner hook center so as not to extend from the inner hook race yarn transfer portion, compared to the conventional example. Thus, the thread transfer groove can be made wider than before without reducing the radial size of the bobbin. Therefore, it is possible to reduce the bending resistance of the yarn without reducing the amount of the lower yarn, realize smooth yarn transfer, and prevent yarn breakage and looping. Further, the bobbin case can be easily processed as compared with the case where the outer periphery of the portion corresponding to the inner hook race yarn transfer portion has the same shape as the inner hook race yarn transfer portion.

[Brief description of the drawings]

FIG. 1 shows a DP shuttle according to a first embodiment of the present invention, wherein (A) is a rear view of the inner shuttle and (B) is a plan view of the inner shuttle and a bobbin case.

FIG. 2 shows a DP hook according to the first embodiment,
(A) is an overall plan view, and (B) is an enlarged plan view of a part of (A).

FIG. 3 shows a DP hook according to the first embodiment,
2A is a cross-sectional side view taken along the line III-III in FIG. 2A, and FIG. 2B is a cross-sectional side view in which a part of FIG.

4A and 4B show a DP shuttle according to a second embodiment of the present invention, wherein FIG. 4A is a rear view of the inner shuttle, and FIG. 4B is a plan view of the inner shuttle and a bobbin case.

FIG. 5 shows a DP hook according to a second embodiment,
(A) is an overall plan view, and (B) is an enlarged plan view of a part of (A).

FIG. 6 is a plan view of a DP hook according to a third embodiment of the present invention.

7A and 7B show a conventional DP hook, wherein FIG. 7A is an overall plan view and FIG. 7B is a BB side view of FIG. 7A.

8A and 8B show a conventional DP hook, wherein FIG. 8A is a plan view of an inner hook and a bobbin case, and FIG. 8B is a plan view of the inner hook.

FIG. 9 is a rear view of the inner pot of the conventional DP pot.

FIG. 10 shows a conventional DP hook, in which (A) is a plan view showing a state in which a needle thread goes around an inner hook and a bobbin case;
(B) is a BB sectional side view of (A).

FIG. 11 is an enlarged cross-sectional side view of a part of FIG.

[Explanation of symbols]

2 Outer hook 4 Inner hook 4c Inner hook center 4b Inner hook race thread transfer section 4b1 Needle thread introduction end 4b2 Needle thread lead-out end 6 Bobbin case 6a Part of bobbin case corresponding to inner hook race thread transfer section 14 Needle thread 16 gap ( Thread transfer groove)

Claims (5)

[Claims] An outer hook having a point for catching a needle thread loop, an inner hook having a needle thread introduction end and a needle thread lead-out end, and an arc formed between the needle thread introduction end and the needle thread lead-out end. An inner hook having a hook race thread transfer section, a bobbin case supported by the inner hook, and a thread transfer groove formed between the outer hook and the inner hook race thread transfer section; In the DP hook, in which the drawn needle thread loop passes through the inner hook and the bobbin case through the thread transfer groove, the radial center of the arc of the inner hook race thread transfer section is moved from the lace thread transfer section to the inner hook center. A sewing machine DP hook that is biased to the far side. 2. The distance between the needle thread introduction end and the center of the inner shuttle is equal to the distance between the needle thread lead-out end and the center of the inner shuttle. 2. The DP hook of a sewing machine according to claim 1, wherein the distance between the needle thread introduction end and the needle thread lead-out end and the center of the inner hook is increased. 3. The distance between the needle thread introduction end and the center of the inner shuttle is shorter than the distance between the needle thread lead-out end and the center of the inner shuttle. The DP hook of a sewing machine according to claim 1, wherein the distance between the needle thread lead-out end and the center of the inner hook is larger than the distance between the needle thread leading end and the center of the inner hook. 4. The bobbin case according to claim 1, wherein the outer periphery of a portion corresponding to the inner hook race yarn transfer section has the same shape as the inner hook race yarn transfer section.
The DP hook of the described sewing machine. 5. An outer periphery of a portion of the bobbin case corresponding to the inner hook race thread transfer section is formed by an arc centered on the inner hook center so as not to extend from the inner hook race thread transfer section. The DP hook of a sewing machine according to claim 1, 2, or 3.