JP4984357B2 - sewing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sewing machine in which a needle stopper for holding a needle is replaceable.
[0002]
[Prior art]
FIG. 10 is a perspective view showing the vicinity of a needle of a conventional flat stitch sewing machine 1. The flat stitch sewing machine 1 has a needle plate 5 mounted horizontally on a sewing machine bed 6, and a plurality of (here, three) needles 4 are provided facing the needle plate 5. The needle 4 is held by the needle stop 3, and the needle stop 3 is fixed to the lower end portion of the needle bar 2 arranged vertically. A crank 66 (see FIG. 12) is connected to the upper portion of the needle bar 2. When the crank 66 rotates, the needle bar 2 reciprocates in the vertical direction, and the needle 4 enters the needle drop hole 9 of the needle plate 5. It is inserted. On the needle plate 5, a presser (not shown) for pressing the cloth is provided. A looper 8 is disposed under the needle plate 5, and the looper 8 swings left and right in synchronization with the reciprocating vertical movement of the needle 4.
[0003]
The sewing operation will be described with reference to FIG. 11. The needle thread 10 is inserted into each needle 4, and the looper thread 11 is inserted into the looper 8. When the needles 4 are raised, a needle thread loop is formed on each needle 4. The looper 8 oscillates so as to crawl all needle thread loops. FIG. 11 (1) is a front view when the looper 8 crawls the needle thread loop, and (2) is a left side view thereof. As can be seen from these figures, the looper 8 passes immediately after the needle 4 and captures the needle thread loop. If the position of the looper 8 and the needle 4 is shifted, the needle thread loop cannot be captured, and a sewing failure called skipping occurs.
[0004]
On the other hand, in a flat stitch sewing machine, one to four needles can be used, and it is necessary to change the number of needles to be used according to the contents of sewing. That is, needle stops according to the number of needles to be used are prepared, such as a needle stop for one needle, a needle stop for two needles, and the needle stopper 3 is replaced when changing the number of needles. .
[0005]
Further, in a flat stitch machine, the needle width (gauge) may be changed. For example, in the case of three needles, the needle width (the dimension from the left needle width center to the right needle width center) may be changed from 5.6 mm to 6.4 mm. Even in such a case, the needle stopper 3 is replaced.
[0006]
FIG. 12 is an exploded perspective view showing a method for replacing the needle stopper 3. A crank 66 is fixed to the tip of the upper shaft 65 built in the sewing machine arm 7. The needle bar rod 17 is rotatably connected to the crank 66. When the upper shaft 65 is rotated to rotate the crank 66, the needle bar rod 17 reciprocates up and down. A needle bar holder 18 is connected to the insertion hole 17 </ b> A at the tip of the needle bar rod 17. The needle bar 2 is inserted into the insertion hole 18 </ b> A of the needle bar holder 18, protrudes downward from the lower surface of the sewing machine arm 7, and a substantially central portion is fixed to the needle bar holder 18 with a set screw 19. Therefore, the needle bar 2 can be reciprocated vertically up and down by rotating the upper shaft 65.
[0007]
A plurality of needles 4 are inserted into the needle clamp 3 from below, and are fixed by needle fixing screws 15 respectively. A screw shaft 16 is integrally formed on the upper portion of the needle stopper 3. The needle bar 2 is a hollow bar, and an inner thread is formed at the lower end. The needle bar 2 and the needle stopper 3 are fixed by screwing the screw shaft 16 of the needle stopper 3 to the lower end of the needle bar. Therefore, when replacing the needle stopper 3, the needle stopper 3 is rotated and removed from the lower end portion of the needle bar 2, and the screw shaft 16 of the new needle stopper 3 is inserted into the lower end of the needle bar 2 and rotated. Tighten and fix.
[0008]
At this time, when the screw has been tightened, it is not known at which angular position the needle stopper 3 is fixed. That is, since the needle clamp 3 and the needle bar 2 are fixed by a screw having the axis L of the needle bar 2 as the center, the position where the needle clamp 3 and the needle bar 2 are tightened and fixed to the end varies depending on the tightening force of the operator, etc. It is not known exactly which position around L.
[0009]
FIG. 13 is a plan view showing the positional relationship between the needle drop hole 9 and the needle 4. As described above, skipping occurs if the positions of the needles 4 are not accurately positioned. Therefore, as shown in FIG. 13B, it is necessary to position the needle stopper 3 so that each needle 4 accurately falls in the center of the corresponding needle drop hole 9.
[0010]
In the case of the three-needle needle clamp 3, the central needle coincides with the axis L of the needle bar 2, so that the positional relationship of the three needles 4 is determined by the tightening force of the screw of the needle clamp 3 as shown in FIG. ) Or ascending to the right as shown in FIG. Therefore, after the needle stopper 3 is fixed to the needle bar 2, the position of the needle bar 2 needs to be adjusted.
[0011]
As shown in FIG. 12, a head cover 12 is provided on the tip surface of the sewing machine arm 7. A through hole 13 is formed in the head cover 12 at a position facing the set screw 19 of the needle bar holder 18. This through hole 13 is normally closed with a plug 14. When replacing the needle stopper 3, the plug 14 is removed. Then, after the new needle stopper 3 is fastened and fixed to the needle bar 2, a screwdriver is inserted through the through hole 13, the set screw 19 is loosened, and the needle bar 2 is rotated so that the position shown in FIG. To perform positioning around the axis L. The height position of the needle 4 is also adjusted by moving the needle bar 2 up and down in the direction of the axis L with the set screw 19 loosened. Thus, after positioning the needle stopper 3 correctly, the set screw 19 is tightened to fix the needle bar 2. Finally, the plug 14 is fitted into the through hole 13 and the replacement operation of the needle stopper 3 is completed.
[0012]
[Problems to be solved by the invention]
Thus, it is very complicated to remove the set screw 19 of the needle bar 2 every time the needle bar 3 is replaced and readjust the positions of the needle bar 2 around the axis L and in the axis L direction. There is a problem that work efficiency is poor.
[0013]
The position of the needle bar 2 is adjusted by inserting a screwdriver through the through hole 13 formed in the head cover 12 and loosening the set screw 19. The tip of the driver inserted through the through hole 13 is screwed into the screw of the set screw 19. It is difficult to fit into the groove, and this also makes the needle stop replacement work complicated.
[0014]
An object of the present invention is to make a sewing machine that makes the needle stopper replacement work itself unnecessary or easy by making the height adjustment of the needle bar and the position adjustment work for the needle drop hole of the needle plate necessary for the needle stopper replacement work unnecessary. Is to provide.
[0015]
[Means for Solving the Problems]
The present invention according to claim 1 is a sewing machine having a needle clamp for holding a needle and a needle bar on which the needle clamp is detachably fixed to the tip.
A detent means for preventing the needle stopper from rotating about the axis of the needle bar, positioning the needle stopper at a predetermined position, and adjusting the position of the needle stopper in the axial direction of the needle bar,
A positioning member provided on the needle bar and having a screw hole;
A detent means having a needle fixing screw screwed into the screw hole of the positioning member is provided,
The needle stop is a flat surface with which the end face of the screwed fixing screw is in contact, and the length of the needle bar in the axial direction is larger than the outer diameter of the end face of the needle fixing screw. A flat surface of the length, an upper end surface of the flat surface that is perpendicular to one end in the axial direction, and a lower end surface of the flat surface that is perpendicular to the other end in the axial direction. A sewing machine characterized by being formed.
In the present invention, the needle stopper is prevented from rotating by screwing a screw onto the needle bar positioning member and bringing the end face of the screw into contact with the needle stopper. In this way, with a simple configuration, the needle stopper can be reliably prevented from rotating and fixed at a predetermined position.
In the present invention, since the needle stopper can be adjusted also in the axial direction of the needle bar, the height position of the needle stopper can be adjusted with the needle bar fixed when the needle stopper is replaced. It is.
[0016]
According to the present invention, a detent means is provided for positioning the needle stopper at a predetermined position around the axis of the needle bar. That is, the anti-rotation means positions the needle stopper at an accurate position around the axis of the needle bar, so there is no need to readjust the position of the needle bar when replacing the needle stopper as in the prior art. Therefore, it is possible to easily replace the needle stopper.
[0023]
According to a second aspect of the present invention, in the rotation preventing means , the needle stopper is positioned at an arbitrary position around the axis of the needle bar and in the axial direction and is fixed by the needle fixing screw.
[0024]
According to the present invention, the needle stopper can be positioned and fixed at an arbitrary position around the axis of the needle bar and in the axial direction. Thus, when the needle stopper is replaced, it is not necessary to readjust the position of the needle bar, and only the needle stopper needs to be adjusted.
[0025]
According to a third aspect of the present invention, the positioning member is a separate member from the needle bar.
[0026]
According to the present invention, since the positioning member and the needle bar are separate members, the manufacturing cost can be reduced as compared with the case where the positioning member and the needle bar are cut and manufactured as an integrated object.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
A first reference example of the present invention will be described with reference to FIGS. The sewing machine of the present invention is the same as the conventional flat stitch sewing machine 1 described with reference to FIGS.
[0028]
FIG. 1 is an exploded perspective view of a needle bar 20 and a needle stopper 21 according to a first reference example , and FIG. 2 is a cross-sectional view showing a connection portion between the needle bar 20 and the needle stopper 21 in a longitudinal direction. FIG. 3 is a cross-sectional view perpendicular to the axis of the connecting portion between the needle bar 20 and the needle stopper 21.
[0029]
The needle bar 20 and the needle stopper 21 are fixed by a positioning member 22 and a needle stopper fixing screw 24. The needle bar 20 is a hollow shaft, and a flat surface 28 is formed on a part of the outer periphery of the lower end portion, and an insertion hole 28a through which the needle fixing screw 24 is inserted is formed so as to penetrate in the radial direction. .
[0030]
The positioning member 22 is an annular member, and has an inner diameter that is substantially equal to the outer diameter of the needle bar 20, and a convex portion 31 that protrudes radially outward is formed on a part of the outer periphery. Is formed.
[0031]
In the needle stopper 21, a needle holding portion 30 that holds a needle and an insertion shaft 26 that is inserted into the hollow needle bar 20 are integrally formed. The lower needle holding portion 30 has a plurality of, here three, needle insertion holes formed in parallel, the needle 23 is inserted into each of them, and each needle fixing screw 25 is fixed individually. An insertion shaft 26 extending in parallel with the needle 23 to be held is provided on the upper part of the needle holding unit 30. The insertion shaft 26 has an outer diameter substantially equal to the inner diameter of the lower end portion of the needle bar 20 and is inserted into the lower end portion of the needle bar 20. A flat surface 27 is formed on the insertion shaft 26.
[0032]
Next, a method for attaching the needle stopper 21 to the needle bar 20 will be described.
First, the positioning member 22 is attached to the lower end of the needle bar 20. At this time, positioning is performed so that the insertion hole 28 a of the needle bar 20 and the screw hole 29 of the positioning member 22 face each other. Next, the insertion shaft 26 of the needle stopper 21 is inserted from the lower end of the needle bar 20. At this time, the insertion surface 26 is positioned and inserted so that the flat surface 27 of the insertion shaft 26 faces the screw hole 29 of the positioning member 22. Then, the needle fixing fixing screw 24 is screwed into the screw hole 29 of the positioning member 22. Then, the needle clamp fixing screw 24 comes into contact with the flat surface 27 of the insertion shaft 26 of the needle clamp 21 through the screw insertion hole 28 a of the needle bar 20.
[0033]
As shown in FIGS. 2 and 3, the needle fixing screw 24 has a tip end surface 33 that is formed flat and perpendicular to the axis of the needle fixing screw 24. Further, the flat surface 27 of the insertion shaft 26 of the needle stopper 21 is a flat surface parallel to the axis of the insertion shaft 26. Therefore, when the needle clamp fixing screw 24 is tightened, the needle clamp 3 is positioned so that the tip surface 33 comes into surface contact with the flat surface 27 of the needle clamp 21. In this manner, the needle stopper 21 is stopped around the axis L of the needle bar 20 and is positioned at a predetermined position around the axis L.
[0034]
As shown in FIG. 2, the insertion shaft 26 of the needle stopper 21 is formed with an upper end surface 34 that is perpendicular to the upper end of the flat surface 27 and a lower end surface 35 that is continuous with the lower end. The distance between the upper end surface 34 and the lower end surface 35 is substantially equal to the outer diameter 33 a of the end portion of the needle fixing screw 24. That is, when the needle clamp fixing screw 24 is screwed, the tip of the needle clamp fixing screw 24 is sandwiched between the upper and lower end surfaces of the insertion shaft 26. That is, the position of the needle stopper 21 in the axial direction of the needle bar 20 is thereby determined.
[0035]
When inserting the needle stopper 21 into the needle bar 20, when the lower end surface of the needle bar 20 comes into contact with the upper end surface 32 of the needle holding portion 30 of the needle stopper 21, the screw insertion hole 28a of the needle bar 20 is inserted. It is positioned at a position facing the flat surface 27 of the shaft 26. Thereby, when the needle fixing screw 24 is inserted, the tip end portion of the needle fixing screw 24 is just fitted between the upper and lower end surfaces 34 and 35 of the insertion shaft 26.
[0036]
Thus, by inserting the needle stopper 21 into the needle bar 20 and tightening the needle fixing screw 24, the needle bar 20 can be positioned around the axis L and in a predetermined position in the axis L direction. Therefore, by positioning the needle bar 20 in advance around the axis L and in the direction of the axis L and fixing the needle bar 20 to the needle bar holder 18, the same position as the previous time can be obtained even when the needle stopper 21 is replaced. Can be positioned. That is, when replacing the needle stopper 21, only the needle stopper 21 can be replaced without adjusting the needle bar 20, and the replacement work of the needle stopper 21 can be performed efficiently.
[0037]
Next, a second reference example of the present invention will be described with reference to FIGS. In this reference example , only the needle fixing fixing screw 24 and the needle stopper 21 of the first reference example are changed, and the other configurations are the same, and thus the description thereof is omitted.
[0038]
The needle fixing screw 40 of this reference example has a tip portion 43 that is not flat but protrudes in a conical shape. Further, a conical recess 44 into which the tip end of the conical needle stopper fixing screw 40 is fitted is formed on the side of the insertion shaft 42 of the needle stopper 41. The recess 44 faces the screw insertion hole 28a of the needle bar 20 when the insertion shaft 42 is inserted into the needle bar 20 and the lower end surface of the needle bar 20 contacts the upper end 32 of the needle holding portion 30 of the needle stopper 41. It is formed in the position to do.
[0039]
Therefore, also in the case of this reference example , when replacing the needle stopper 41, the needle stopper fixing screw 40 is removed, the needle stopper 41 is removed, a new needle stopper 41 is attached, and the needle stopper fixing screw 40 is attached. The needle stopper 41 is replaced by screwing. At this time, the tip end portion of the needle clamp fixing screw 40 has a conical shape, and the recess 44 formed in the insertion shaft 42 of the needle clamp 41 also has a conical shape. At this time, the tip 43 is fitted into the recess 44, so that the needle stopper 41 is accurately positioned at a predetermined position in the direction of the axis L of the needle bar 20 and around the axis L.
[0040]
It will now be described implementation form of the present invention with reference to FIGS. FIG. 7 is an exploded perspective view of the needle stopper 50 and the needle bar 20 according to the present embodiment, and FIG. 8 is a cross-sectional view of the needle stopper 50 and the needle bar 20 that are partially cut away.
[0041]
In this embodiment, since only the needle clamp is different from the first reference example , the description of other configurations is omitted. In the needle stopper 50 of the present embodiment, the flat surface 52 of the insertion shaft 51 is formed longer than the flat surface 27 of the first reference example . This makes it possible to adjust the fixed position of the needle bar 50 in the axial direction of the needle bar 20. That is, as shown in the cross-sectional view of FIG. 8, the length between the upper and lower end surfaces 53, 54 of the flat surface 52 is formed to be larger than the outer diameter 33 a of the tip end portion of the needle fixing screw 24. Thereby, the needle stopper 50 can be fixed at an arbitrary position between the upper and lower end surfaces 53 and 54. Further, the needle fixing screw 24 may be set in contact with the upper end surface 53 and the lower end surface 54 for positioning.
[0042]
With such a configuration, for example, even when it is necessary to change the height position of the needle with the replaced needle, it is not necessary to adjust the height position of the needle bar 20, and only the needle stopper 50 can be replaced. That's it.
[0043]
Next, a third reference example of the present invention will be described with reference to FIG. Since this reference example is different from the first reference example only in the needle clamp, the description of other configurations is omitted.
[0044]
The insertion shaft 61 of the needle stopper 60 of the present reference example is a cylindrical shaft on which no flat surface is formed. With such a configuration, the needle clamp 60 can be positioned and fixed at an arbitrary position around the axis L of the needle bar by the needle clamp fixing screw 24. Similarly, the needle bar 20 can be positioned and fixed at an arbitrary position in the axis L direction.
[0045]
Also in this reference example , the needle stopper 21 can be replaced only by changing the needle stopper 60 without adjusting the position of the needle bar 2. At this time, the needle stopper 60 can be fixed at an arbitrary position. Therefore, the needle stopper 60 is fixed after positioning with respect to the needle bar 20 around the axis L and in the axis L direction. Thus the present embodiment, ing greater freedom of positioning.
[0046]
Further, in order to increase the contact area between the needle clamp fixing screw 24 and the insertion shaft 61, the tip surface of the needle clamp fixing screw 24 may be curved in an arc shape. By increasing the contact area in this way, the needle stopper 21 can be fixed with a large force.
[0047]
The implementation described above, the positioning member 22, the needle bar 20 and the separate, and configured to separately manufactured. In this way, it can be manufactured at low cost by forming it separately. However, the present invention is not limited to such a case, and the needle bar 20 and the positioning member 22 may be integrally formed by cutting, for example. Is possible.
[0048]
Although in the implementation embodiments described above the sewing machine has been described as flat stitch sewing machine, the present invention is not limited thereto, the needle clamp if sewing machine has a detachable interchangeable consist needle bar Applicable.
[0049]
【Effect of the invention】
As described above, according to the present invention, since the anti-rotation means for positioning the needle stopper at a predetermined position around the axis of the needle bar is provided, the needle stopper can be positioned at an accurate position around the axis, Unlike the prior art, it is not necessary to readjust the position of the needle bar, and the needle stopper replacement operation can be performed efficiently.
In addition, the needle stopper can be reliably prevented from rotating by the end face formed on the needle stopper and the front end face of the needle stopper fixing screw contacting the end face, and can be fixed at a predetermined position.
Further, since the needle stopper can be adjusted also in the axial direction of the needle bar, the height position of the needle can be adjusted by adjusting only the needle stopper without adjusting the needle bar in the axial direction.
[0053]
Further, according to the present invention, the needle stopper can be positioned and fixed at any position around the axis of the needle bar and in the axial direction. As a result, the position of the needle stopper can be adjusted around and in the axial direction with the needle bar fixed.
[0054]
Further, according to the present invention, since the positioning member and the needle bar are separate members, the manufacturing cost can be reduced as compared with the case where the positioning member and the needle bar are cut and manufactured as an integrated object.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a first reference example .
FIG. 2 is a cross-sectional view in which a connecting portion between a needle bar 20 and a needle stopper 21 is cut away in the vertical direction.
FIG. 3 is a cross-sectional view perpendicular to the axis of a connecting portion between a needle bar 20 and a needle stopper 21;
FIG. 4 is an exploded perspective view of a second reference example .
FIG. 5 is a cross-sectional view showing a connecting portion between a needle bar 20 and a needle stopper 41 cut out in a vertical direction.
6 is a cross-sectional view perpendicular to the axis of a connecting portion between a needle bar 20 and a needle stopper 41. FIG.
7 is an exploded perspective view of the implementation forms.
FIG. 8 is a cross-sectional view showing a connecting portion between a needle bar 20 and a needle stopper 50 cut out in the vertical direction.
FIG. 9 is an exploded perspective view of a third reference example .
FIG. 10 is a perspective view showing the vicinity of a needle of a conventional flat stitch sewing machine 1;
11A is a front view when the looper 8 crawls the needle thread loop, and FIG. 11B is a left side view thereof.
12 is an exploded perspective view showing a connection state between a conventional needle bar 2 and a needle stopper 3. FIG.
13 is a plan view showing the positional relationship between the needle drop hole 9 and the needle 4. FIG.
[Explanation of symbols]
20 Needle bar 21, 41, 50, 60 Needle clamp 22 Positioning member 24, 40 Needle clamp fixing screw

Claims (3)

In a sewing machine having a needle stopper for holding a needle and a needle bar on which the needle stopper is detachably fixed to the tip portion,
A detent means for preventing the needle stopper from rotating about the axis of the needle bar, positioning the needle stopper at a predetermined position, and adjusting the position of the needle stopper in the axial direction of the needle bar,
A positioning member provided on the needle bar and having a screw hole;
A detent means having a needle fixing screw screwed into the screw hole of the positioning member is provided,
The needle stop is a flat surface with which the end face of the screwed fixing screw is in contact, and the length of the needle bar in the axial direction is larger than the outer diameter of the end face of the needle fixing screw. A flat surface of the length, an upper end surface of the flat surface that is perpendicular to one end in the axial direction, and a lower end surface of the flat surface that is perpendicular to the other end in the axial direction. A sewing machine characterized by being formed. 2. The sewing machine according to claim 1, wherein in the anti-rotation means, the needle stopper is positioned at an arbitrary position around the axis of the needle bar and in the axial direction and fixed by the needle fixing screw. The sewing machine according to claim 1 or 2, wherein the positioning member is a separate member from the needle bar.

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