JP4564163B2 - DP hook of sewing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vertical full 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]
[Prior art]
The DP hook according to the conventional example (the hook in which the sword tip of the outer hook is located between the needle drop position and the lower needle thread leading point of the bobbin) is supported by the outer hook 2 and the outer hook 2 as shown in FIGS. 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 race portion 4 a at the circumferential portion thereof, and the race portion 4 a is fitted into the race groove 2 d of the outer hook 2. A portion of the lace portion 4a is cut away to form an inner hook race thread crossing portion 4b. The left and right ends of the inner hook race thread crossing portion 4b are a needle thread introducing end 4b1 and a needle thread leading end 4b2. The lace yarn crossing portion 4b is formed by an arc having a radius R1 with the center 4c of the inner hook 4 being the center. Accordingly, 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 are both R1. R1 is smaller than the outer radius of the race portion 4a.
[0004]
A portion 6a of the bobbin case 6 corresponding to the inner hook lace yarn passing portion 4b has the same shape as the inner hook lace yarn passing portion 4b. That is, the outer periphery of the portion 6a corresponding to the inner hook race thread crossing portion 4b is formed by an arc having a radius R1 with the center 4c of the inner hook 4 being the center.
[0005]
As shown in FIGS. 10 and 11, the inner hook 4 is fixed so that the race yarn crossing portion 4 b is positioned upward. When the workpiece 10 is placed on the needle plate 8 and the sewing machine main shaft (not shown) is rotated, the needle thread 14 captured by the sword tip 2c is moved by the vertical movement of the needle 12 and the rotation of the outer hook 2 in the direction A. Is rotated around the inner hook 4 and the bobbin case 6. 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 the inner hook race thread crossing portion 4b. It moves from the needle thread introduction end 4b1 side to the needle thread lead-out end 4b2 side while contacting with the needle thread.
[0006]
[Problems to be solved by the invention]
Since the thickness of the bobbin case 6 cannot be increased due to the structure of the DP hook, the amount of bobbin thread accommodated therein is increased by increasing the thickness in the radial direction as much as possible. For this reason, a gap (thread passing groove) 16 through which the needle thread 14 passes between the inner hook race thread crossing portion 4b and the outer hook 2 (inner hook presser 2b) is narrowed (for example, about 0.6 mm). As the bending resistance increases, a thick thread or a thread having a large frictional resistance may cause a phenomenon that the thread does not pass smoothly, and sometimes sewing failure such as thread breakage or looping may occur.
[0007]
An object of the present invention is to make a DP hook for a sewing machine capable of widening a gap (thread passing groove) through which a needle thread passes between an inner hook race thread crossing portion and an inner hook presser without reducing the amount of bobbin thread. Is to provide.
[0008]
[Means for Solving the Problems]
To achieve the above object , according to the first or second aspect of the present invention, an outer hook having a sword that captures a needle thread loop, a needle thread introduction end, a needle thread lead-out end, and the needle thread introduction end; An inner hook having an inner hook race thread crossing portion which is formed in an arc shape between the needle thread leading ends and moves while the needle member and the loop captured by the outer hook are in contact with each other, and a bobbin supported by the inner hook A case and a thread passing groove formed between the outer hook and the inner hook race thread passing portion, and the needle thread loop captured by the sword tip passes through the thread passing groove and the inner hook and the bobbin case. In the DP hook that passes through, in order to increase the gap through which the thread passes, the radius center of the arc of the inner hook race thread crossover part is biased to the side farther from the race thread crossover part than the inner hook center, The distance between the needle thread introduction end and the inner hook center is the needle thread lead-out. And shorter than the distance between the bobbin case center, the radius of the arc of the inner hook race thread connecting portions, larger than the distance between the needle thread out end and bobbin case center.
[0011]
In the first aspect of the invention, it is preferable that an outer periphery of a portion of the bobbin case corresponding to the inner hook race thread jumper has the same shape as the inner hook race thread jumper.
[0012]
According to a second aspect of the present invention, the outer periphery of a portion of the bobbin case corresponding to the inner hook race thread crossing portion is an arc centered on the inner hook center so as not to extend from the inner hook race thread crossing portion. it can be formed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the DP hook according to the present invention will be described with reference to the drawings.
[0014]
1 to 3 show a DP hook according to the first embodiment. This DP hook has an outer hook 2, a back plate 2a fixed to the outer hook 2, an inner hook presser 2b fixed to the outer hook 2, an inner hook 4 supported by the outer hook 2, The bobbin case 6 is supported by the hook 4. The inner hook 4 is provided with a lace portion 4a made of a synthetic resin at a circumferential portion thereof, and the lace portion 4a is fitted into the race groove 2d of the outer hook 2. A portion of the lace portion 4a is cut away to form an inner hook race thread crossing portion 4b. The lace yarn crossing portion 4b has a needle yarn introduction end 4b1 and a needle yarn outlet end 4b2 at both ends thereof. The lace yarn crossing portion 4b may be made of steel, but if it is made of synthetic resin, it can be easily molded, and thus is suitable for application of the present invention.
[0015]
In the present embodiment, the shape of the arc of the lace yarn crossover 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 lace yarn crossover 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 thread crossover portion 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 ( L1 = L2 = R1) where R1 is the radius of the arc of the lace yarn crossover portion 4b according to the conventional example, but the center of the arc of the lace yarn crossover portion 4b is the inner hook lace yarn crossover with respect to the inner hook center 4c. It is biased toward the side farther from the portion 4b (the lower side in the figure). Therefore, when the radius of the arc of the lace yarn crossing portion 4b according to the present embodiment is R2, R2> L1 = L2 = R1. Further, the outer periphery of the portion 6a of the bobbin case 6 corresponding to the inner hook race crossover portion 4b is also shaped to have the same arc as the race yarn crossover portion 4b.
[0016]
According to the present embodiment, the gap (yarn passing groove) 16 through which the needle thread passes between the inner hook race thread crossover portion 4b and the inner hook presser 2b is reduced without reducing the size of the bobbin case 6 in the radial direction. It can be made larger than the other pot. Accordingly, the bending resistance of the needle thread is reduced, the smooth and crossing can be realized, and thread breakage and looping can be prevented.
[0017]
4 and 5 show a DP hook according to the second embodiment. This DP hook is different 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 crossing portion 4b is shorter than that of the conventional, and the needle thread from the inner hook center 4c to the needle thread. The distance L4 to the lead-out end 4b2 is set to R1 as in the conventional example, and the center of the arc of the inner hook race thread crossover portion 4b is farther from the inner hook race thread crossover section 4b than the inner hook center thread 4c (the lower side in the figure). ). When the radius of the arc of the lace yarn crossing portion 4b according to this embodiment is R3, R3> L4 = R1> L3 . Further, the outer periphery of the portion 6a of the bobbin case 6 corresponding to the lace yarn jumping portion 4b has a shape having the same arc as that of the lace yarn jumping portion 4b.
[0018]
According to the present embodiment, the gap through which the yarn passes between the inner hook race thread crossing portion 4b and the inner hook presser 2b without reducing the radial size of the bobbin case 6 as in the first embodiment. Since 16 can be made larger than a conventional hook, the yarn crossing becomes smooth. Further, in the case of the present embodiment, since the gap 16 on the side of the needle thread introduction end 4b1 is widened, a sewing failure due to biting or the like when the needle thread is introduced is prevented.
[0019]
FIG. 6 shows a DP hook according to the third embodiment. Since the inner hook 4 of the DP hook has the same structure as that of the second embodiment, the description thereof is omitted. The outer periphery of the portion 6a of the bobbin case 6 corresponding to the inner hook race thread transfer portion 4b is sized so as not to protrude and protrude with respect to the shape of the inner hook race thread transfer portion 4b (bobbin It is also the center of the case 6).
[0020]
According to the present embodiment, in addition to the same effects as those of the second embodiment, the center of the outer shape of the portion 6a corresponding to the inner hook race thread crossing portion 4b of the bobbin case 6 is the center of the bobbin case 6. The molding process is easy and there is an effect of cost reduction.
[0021]
As mentioned above, although this invention was demonstrated based on embodiment shown in drawing, this invention is not limited to these embodiment, A various deformation | transformation is possible. For example, the inner hook 4 of the third embodiment has the same structure as that of the second embodiment, but has the same structure as the inner hook of the first embodiment and corresponds to the inner hook race thread crossing portion 4b. The outer periphery of the portion 6a of the bobbin case 6 can be formed in a circular arc shape having a center at the inner hook center 4c in such a size that it does not protrude from the shape of the inner hook race thread crossover portion 4b.
[0022]
【The invention's effect】
According to the present invention, the outer hook having a sword that captures the needle thread loop, the needle thread introducing end and the needle thread leading end are formed in an arc shape between the needle thread introducing end and the needle thread leading end. An inner hook having an inner hook lace yarn passing portion, a bobbin case supported by the inner hook, and a yarn passing groove formed between the outer hook and the inner hook lace yarn passing portion are captured by the sword tip. In the DP hook where the needle thread loop passes through the inner hook and the bobbin case through the thread passing groove, the radius center of the arc of the inner hook race thread moving section is biased to the side farther from the race thread moving section than the inner hook center. By doing so, the yarn passing groove can be made wider than before, the bending resistance of the yarn is reduced, the yarn passing is smoothly performed, and yarn breakage and looping can be prevented.
[0024]
Furthermore, since the thread crossing groove on the needle thread introduction end side is widened, poor sewing due to biting or the like when the needle thread is introduced is prevented.
[0025]
When the outer periphery of the part corresponding to the inner hook race thread crossing part of the bobbin case has the same shape as the inner hook race thread crossing part, the thread crossing is made without reducing the radial size of the bobbin compared to the conventional example. The groove can be made wider than before. Therefore, it is possible to reduce the bending resistance of the yarn without reducing the bobbin thread amount, to achieve smooth yarn crossing, and to prevent yarn breakage and looping.
[0026]
When the outer periphery of the portion corresponding to the inner hook race thread crossing portion of the bobbin case is formed with an arc centering on the inner hook center so as not to extend from the inner hook race thread crossing portion, the bobbin The yarn crossing groove can be made wider than before without reducing the size in the radial direction. Therefore, it is possible to reduce the bending resistance of the yarn without reducing the bobbin thread amount, to achieve smooth yarn crossing, and to prevent yarn breakage and looping. Furthermore, 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 thread transfer portion has the same shape as the inner hook race thread transfer portion.
[Brief description of the drawings]
1A and 1B show a DP hook according to a first embodiment of the present invention, in which FIG. 1A is a rear view of the inner hook, and FIG. 1B is a plan view of the inner hook and a bobbin case.
FIGS. 2A and 2B show a DP hook according to the first embodiment, in which FIG. 2A is a plan view of the whole, and FIG. 2B is an enlarged plan view of a part of FIG.
FIGS. 3A and 3B show a DP hook according to the first embodiment, wherein FIG. 3A is a sectional side view taken along the line III-III in FIG. 2A, and FIG. 3B is an enlarged sectional side view of part of FIG. is there.
4A and 4B show a DP hook according to a second embodiment of the present invention, in which FIG. 4A is a rear view of the inner hook, and FIG. 4B is a plan view of the inner hook and a bobbin case.
5A and 5B show a DP hook according to a second embodiment, in which FIG. 5A is an overall plan view, and FIG. 5B is an enlarged plan view of a part of FIG.
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, in which FIG. 7A is a plan view of the whole, and FIG. 7B is a side view taken along line BB of FIG.
8A and 8B show a conventional DP hook, wherein FIG. 8A is a plan view of the inner hook and the 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 hook.
10A and 10B show a conventional DP hook, in which FIG. 10A is a plan view showing the needle thread turning around the inner hook and the bobbin case, and FIG. 10B is a side view taken along the line BB in FIG.
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 lace thread transfer part 4b1 Needle thread introduction end 4b2 Needle thread lead-out end 6 Bobbin case 6a Bobbin case part 14 corresponding to the inner hook race thread transfer part 14 Needle thread 16 Clearance ( Yarn crossing groove)

Claims (2)

An outer pot having a sword tip for capturing a needle thread loop;
The needle thread introducing end and the needle thread leading end are formed in an arc shape between the needle thread introducing end and the needle thread leading end, and the needle thread captured by the outer hook and the loop move while contacting each other. An inner hook having a hook race thread crossing section;
A bobbin case supported by the inner hook;
A yarn passing groove formed between the outer hook and the inner hook race yarn passing portion;
In the DP hook in which the needle thread loop caught by the sword tip passes through the inner thread and the inner hook and the bobbin case,
In order to increase the gap through which the yarn passes, the radius center of the arc of the inner hook race thread crossing portion is biased to the side far from the race yarn crossing portion with respect to the inner hook center,
The distance between the needle thread introducing end and the inner hook center is made shorter than the distance between the needle thread leading end and the inner hook center, and the radius of the arc of the inner hook race thread crossing portion is set to the needle thread leading position. Larger than the distance between the end and the inner pot center,
A DP hook for a sewing machine, characterized in that an outer periphery of a portion of the bobbin case corresponding to the inner hook race thread crossing portion has the same shape as the inner hook race thread crossing portion . An outer pot having a sword tip for capturing a needle thread loop;
The needle thread introducing end and the needle thread leading end are formed in an arc shape between the needle thread introducing end and the needle thread leading end, and the needle thread captured by the outer hook and the loop move while contacting each other. An inner hook having a hook race thread crossing section;
A bobbin case supported by the inner hook;
A yarn passing groove formed between the outer hook and the inner hook race yarn passing portion;
In the DP hook in which the needle thread loop caught by the sword tip passes through the inner thread and the inner hook and the bobbin case,
In order to increase the gap through which the yarn passes, the radius center of the arc of the inner hook race thread crossing portion is biased to the side far from the race yarn crossing portion with respect to the inner hook center,
The distance between the needle thread introducing end and the inner hook center is made shorter than the distance between the needle thread leading end and the inner hook center, and the radius of the arc of the inner hook race thread crossing portion is set to the needle thread leading position. Larger than the distance between the end and the inner pot center,
A DP of a sewing machine characterized in that an outer periphery of a portion of the bobbin case corresponding to the inner hook race thread crossing portion is formed by an arc centering on the inner hook center so as not to extend from the inner hook race thread crossing portion. Kettle.

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