JPH0744305Y2 - Cycle sewing machine for buttonholes - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is for buttonhole overlocking, in which the needle is swung to form a zigzag stitch around the buttonhole to perform buttonhole overlocking. Cycle sewing machine

[Prior Art] Currently, as a sewing machine of this type, a cloth for forming a button hole is linearly reciprocated by rotation of a cam plate that is interlocked with a main shaft of a sewing machine, and a needle that moves up and down is conveyed by a swing mechanism. While performing zigzag stitching by swinging in a direction orthogonal to the direction, the zigzag stitching base line is interlocked with a cam plate that rotates with the sewing machine main shaft to change the zigzag stitching base line as shown in FIG. It is known to form a stitch as shown in FIG. 8 around the buttonhole while appropriately changing the swing width.

As shown in the figure, in the conventional sewing machine of this type, first, a first parallel stitch portion S1 is formed along the first base line 1 at the same position as the button hole forming line 1, and then the first base line 1 is formed. Along the slanted second base line l2 connected to the end of the slanted seam S2
Is formed, and when the formation of this inclined seam S2 is completed,
In conjunction with the cam plate described above, the swing width of the needle is converted to twice the width (2t1) of that time, and the base line is converted to the third base line l3 parallel to the first base line 1, thus Bar-tacking portions S3 are formed.

After the formation of this bartack S3, the original swing width t1 is changed again,
A second parallel stitch portion S4 is formed along the third base line l3.
After the formation of the second parallel stitch portion S4, the swing width of the needle is converted to 2t1 and the second bar-tack portion S5 is formed along the third base line l3.

As described above, in the conventional cycle sewing machine for buttonhole sewing, the swing width of the needle at the bar-tacking portions S3 and S5 is set to the other portion S
By setting the swing width of the needle at 1, S2, S4 to twice, the contour lines of the bartack portions S3, S5 and the contour lines of the first and second parallel stitch portions S1, S4 are continuous. It is designed to form seams with an excellent appearance.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technique, an inclined seam portion formed from the terminal end of the first parallel seam portion S1 to the starting end of the first bar-tacking portion S3. Since S2 is formed with the same stitch width (needle swing width) t1 as that of the parallel stitch portion S1, the needle is already formed when the end of the first bar-tacking portion S3 is sewn. It falls between the end of the first parallel seam S1 and the start of the inclined seam S2 (indicated by d in FIG. 8 (b)), and occurs between the seam and the needle thread. Inconveniences such as needle thread and stitch thread were frequently cut due to friction and entanglement of threads.

Even when the second bar-tacking portion S5 is formed, the needle falls into the first parallel seam portion S1. Therefore, there is a concern that thread breakage may occur as in the case of the first bar-tacking portion S3. However, when the second bar-tacking portion S5 is formed, the driving of the sewing machine is switched to the low-speed driving in preparation for the stop, so that the occurrence of the yarn breakage as described above is extremely small.

The present invention has been made in view of the above problems, in which thread breakage does not occur at the time of forming the bartack seam portion, and moreover, the bartack portion and the first and second parallel seam portions are formed. It is an object of the present invention to provide a cycle sewing machine for buttonholes which does not impair the continuity of the button sewing machine.

[Means for Solving the Problems] In the invention, in a buttonhole cycle sewing machine in which a bartacking cam of a main cam 3 is used to form a bartacking stitch, a swinging mechanism of a needle is synchronized with a lifting and lowering of the needle. Of the oscillating link 21 and the oscillating link that interlocks with the eccentric cam. The swinging fulcrum 22 is moved to change the swing width (sewing width) of the needle bar at the bartacking portion to be smaller than the sewing width of the parallel seam of the button seam.

[Operation] In this invention, since the stitches are formed in the bartack portion with a stitch width smaller than the parallel stitch width of the button stitch, the needle does not interfere with the parallel stitch.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to FIGS. 1 to 6.

In the figure, reference numeral 1 is a needle bar rocking base whose upper end is swingably held by a sewing machine frame by a shaft 1a. The needle bar rocking base 1 is moved up and down in conjunction with a sewing machine main shaft (not shown). The needle bar 2a is held, and the needle 2b is fixed to the lower end of the needle bar 2a. Three
Is a disk-shaped main cam whose center is fixed to a rotary shaft 4 that rotates in conjunction with the sewing machine main shaft. This main cam 3 makes one rotation for one cycle of buttonhole sewing, and this rotation causes the outside of the figure. The cloth conveying member of FIG. Reference numeral 5 denotes an annular base line conversion cam projectingly provided on the upper surface of the main cam 3. The cam surface 5a of the cam 5 has a first base line portion.
5a1, the second base line portion 5a2, and the third base line portion 5a3 are formed at different heights.

Reference numeral 6 denotes an annular swing width conversion cam that is also provided on the upper surface of the main cam 3 and is located outside the base line conversion cam 5.
A groove portion 6a2 is formed on the cam surface 6a, and the other portions (high portions) 6a1 are set to the same height.

As shown in FIG. 4, the groove portion 6a2 is configured to be lower than the cam surface of the swing width conversion cam 6 by approximately the length of the bar-tacking cam 7a from the end portion of the bar-tacking cam 7a and the base-line conversion cam. 5 is provided in the same rotation phase as the second base line portion 5a2. Reference numerals 7a and 7b denote first and second bartacking cams projectingly provided on the upper surface of the main cam 3, respectively, projecting on the same circumference outside the swing width cam 6, 7a, 7b cam surface 7a
1, 7b1 have the same height, and the height is set higher than the cam surface 6a1 of the swing width conversion cam 6. The start end of the cam surface 7a1 of the first bartack cam 7a among the bartack cams 7a and 7b is the start end of the third baseline part 5a3 of the baseline conversion cam 5 (the end part of the second baseline part 5a2). ), And the end of the cam surface 7b1 of the second bartack portion 7b is in the same rotation phase as the end of the third base line portion 5a3. ing.

Further, 8 is a base line converting arm as a base line converting mechanism for changing a base line which is a reference of rocking of the needle, 9 is a rocking width converting arm, 10 is a bartacking operation arm, and these arms 8, 9, 10 are An intermediate portion is rotatably supported by a shaft 11.

Further, a copying roller is provided at the tip of each of the arms 8, 9 and 10.
8a, 9a, 10a are provided, among these rollers
The copying roller 8a is on the cam surface 5a of the base line conversion cam 5, the copying roller 9a is on the cam surface 6a of the swing width conversion cam 6, and the copying roller 10a.
Is always in pressure contact with the cam surface 7a1 of the bartack cam 7a or the upper surface of the main cam.

Therefore, the swing width converting arm 9 follows the cam surface of the swing width converting cam and the swing link 21 to be described later according to the height of the cam surface.
The swing fulcrum of moves and the size of the swing width of the needle changes.

The swing width converting cam 6, the groove 6a2 and the swing width converting arm 9 constitute a swing width converting mechanism for changing the swing width of the needle.

Reference numeral 12 is a base line conversion rod in which an intermediate portion is rotatably attached to a shaft 13 supported by a machine frame of the sewing machine.
The a is always in contact with the upper end of the base line converting arm 8.

Reference numeral 14 is a swing width conversion rod having an intermediate portion rotatably attached to a shaft 15 supported by a sewing machine frame, and the lower end of the swing width conversion arm 9 has an upper end portion of the swing width conversion arm 9 and a bartacking operation arm 10. Two adjusting screws are provided so as to be opposed to the upper end portion, and one of the adjusting screws 14a or 14b is always in contact with the arm 9 or 10.

Reference numeral 16 denotes a link whose lower end is rotatably connected to the upper end of the swing width conversion rod 14, and whose upper end is rotatably connected to one side surface of a U-shaped frame 18 by a shaft 17. There is. Further, on one side surface of the frame body 18, the upper end portion of the base line conversion rod 12 is also provided with a shaft 19
It is rotatably attached by. Reference numeral 20 is a bifurcated link whose one end is rotatably mounted in the frame 18 by the shaft 17, and 21 is a swinging link whose one end is rotatably connected to the bifurcated link 20 by a shaft 22, and the other end. The part is rotatably connected by a shaft 25 to the other end of a connecting arm 24 whose one end is fixed to the connecting shaft 23. The swing link 21 has a bifurcated shape, and the bifurcated portion 21a is fitted with an eccentric cam 27 fixed to a rotary shaft 26 that rotates in conjunction with the sewing machine main shaft.

The connecting shaft 23 is rotatably held on the machine frame of the sewing machine, and the other end thereof is connected to the needle bar rocking base 1 via a connecting member 28.

The shaft 17, the swing link 21, and the eccentric cam 27 are used to
A swinging mechanism that swings 2b in a direction orthogonal to the cloth conveying direction in synchronization with the raising and lowering thereof is configured.

The buttonhole overedging cycle sewing machine in this embodiment is configured as described above, and when the sewing machine main spindle starts to rotate and the needle 2b starts moving up and down and the cloth conveying operation, it interlocks with this. The main cam 3 and the eccentric cam 27 rotate,
A first parallel portion S1 is formed in which the needle 2b is set at the same position as the button hole forming line (see FIG. 6 (a)). At this time, the swing of the needle is performed as follows.

That is, when the eccentric cam 27 rotates, the swing link 21 fitted to the eccentric cam 27 is pushed up and down, so that the bifurcated link 20 connected thereto swings about the shaft 17 and swings. In order to swing the link 21, the connecting shaft 23 rotates and swings via the connecting arm 24, and the needle bar swing base 1 swings about the shaft 1a as a fulcrum in a direction orthogonal to the cloth conveying direction.

Therefore, the needle bar 2a swings while moving up and down in the needle bar swing base 1,
Staggered sewing is performed.

Further, during sewing of the first parallel portion S1, the copying roller 8a of the base line converting arm 8 follows the first base line portion 5a1 of the base line converting cam 5,
The copying roller 9a of the swing width converting arm 9 follows the high portion 6a1 of the swing width converting cam 6, and the copying roller 10a of the bartacking operation arm 10 is the main cam 3
Is imitating the upper surface of.

Here, when the sewing of the first parallel stitch S1 proceeds to just before the end of the first base line 1, the copying roller 9a of the swing width converting arm 9 moves the swing width converting cam 6 as shown in FIG. 2, the swing converting arm 9 rotates clockwise in FIG. As a result, the swing width conversion rod 14 rotates counterclockwise about the shaft 15 and pulls the frame 18 downward via the connecting link 16, so that the frame 18 rotates about the shaft 19.

Therefore, since the main shaft 17 moves downward at the rotary swing fulcrum of the bifurcated link 20, the swing amount transmitted to the connecting arm 24 via the swing link 21 decreases, and the rotary swing angle of the connecting shaft 23 decreases. To do. As a result, the swing width of the needle bar 2a that swings together with the needle bar swing base 1 decreases, and the stitch width formed on the cloth W changes from t1 to t2 (t1
> T2).

When the sewing reaches the end of the first base line 1, the copying roller 8a of the base line converting arm 8 tilts upward to the second base line portion.
Riding on 5a2, the baseline converting arm 8 rotates counterclockwise around the axis 11.

Then, in conjunction with this, the base line conversion rod 12 rotates clockwise in FIG. 2, and the swing link 21 gradually moves in the arrow a direction via the frame 18 and the forked link 20. Therefore, the connecting shaft 23 rotates via the connecting arm 24 along with the movement,
The needle bar 2a gradually rotates counterclockwise in FIG. 2, whereby the needle 2b is swung based on the second base line l2 which is inclined with respect to the cloth conveying direction, and is inclined. A seam portion S2 is formed. The inclined portion S2 is formed with the stitch width t2 exchanged immediately before the end of the parallel stitch portion S1.

When the sewing of the inclined seam S2 progresses to the end of the second baseline,
The copy roller 10a of the bartacking operation arm 10 rides on the cam surface 7a1 of the first bartacking cam 7a, and the bartacking operation arm 10 rotates counterclockwise about the shaft 11. As a result, the bar-tacking operation arm 10
The lower end of the swing width conversion rod 14 is pressed via 14b,
Is rotated clockwise about axis 15.

As a result, the frame 18 is pulled by the connecting link 16 and rotates about the shaft 19, and the shaft 17, which is the swing fulcrum of the bifurcated link 20, moves upward. As a result, the swing link 21 to the connecting member 24
The swing amount transmitted to the needle increases and the rotation swing angle of the connecting shaft 23 increases, so that the needle swing width increases and the stitch width increases to t3. This stitch width t3 is enlarged to twice the stitch width t1 in the above-mentioned first parallel portion S1. At the same time, the copying roller 8a of the base line converting arm 8 contacts the flat third base line portion 5a3 from the end of the second base line portion l2 and is held at a fixed position.

Therefore, the reference position for swinging the needle 2b is held on the third base line parallel to the button hole forming line 1. Further, the distance between the third reference line l3 and the button hole forming line l is equal to the parallel stitch portion.
It is the same as the width t1 of S1.

Therefore, after forming the inclined seam S2, the needle 2b forms the first bar-tack S3 while falling on the extension line of the third base line 13 and the outline L1 of the first parallel seam S1.

Then, the first bar-tacking portion S3 is formed to overlap the already formed slanted stitch portion S2 and the first parallel stitch portion S1. However, at this time, the stitch width t2 of the terminal end portion S1a of the first parallel stitch portion S1 and the inclined stitch portion S2 becomes smaller than the stitch width t1 at the start of sewing of the first parallel stitch portion S1. Therefore, the needle 2b does not drop into these stitches, and there is no risk that the needle thread will be cut due to friction or entanglement with the stitch thread as in the conventional case.

When the first bar-tacking portion S3 is formed to have a predetermined length as described above, the copying roller 10a of the bar-tacking operation arm 10 falls from the bar-tacking cam 7a to the upper surface of the main cam 3 and the bar-tacking operation arm 10a. 10 rotates clockwise in FIG.

Following this, the swing width conversion rod 14 rotates counterclockwise,
It contacts the upper end of the swing width converting arm 9 through the adjusting screw 14a. At this time, since the copying roller 9a of the swing width converting arm 9 follows the high portion 6a of the swing width converting cam 6, the swing width converting rod 14
Is held at the same position as when sewing the above-mentioned first parallel stitch portion S1, and the swing width of the needle 2b is the swing width t1 of the first parallel stitch portion S1.
Is converted to the same width as. Further, since the copying roller 8a of the base line converting arm 8 continuously follows the third base line portion 5a3,
The needle bar 2a swings along the third base line l3, and the second parallel stitch portion
S4 is formed.

After that, when the sewing of the third parallel stitch portion S4 is completed, the cloth conveying member (not shown) is driven at a low speed, and the swing width of the needle is equal to the width t3 of the first bar-tacking portion S3. Converted to the same width. This swing width conversion is performed by the second bar-tacking cam provided on the main cam 3.
Done by 7b. As a result, the second bar-tacking portion S5 is formed so as to overlap the already formed first parallel stitch portion S1.
With the above, a series of buttonhole sewing operations ends.
In the sewing of the second bar-tacking portion S5, the needle falls into the first parallel stitch portion S1. However, since the sewing speed at this time is low, there is almost no possibility of thread breakage. .

Further, in the seam formed as described above, the left and right outlines of the first and second bar-tacking portions S3 and S5 are the first and second outlines.
Since it matches the outline of the parallel seams S1 and S4, the appearance continuity of each seam S1, S2, S3, S4 and S5 is maintained and excellent sewn product quality can be obtained. .

In the above embodiment, the first and second bar-tacking portions S3,
Of S5, the first parallel stitch portion S1 overlapping the first bar-tacking portion S3
Although only the end portion of S and the stitch width of S2 are narrowed, the stitch portion overlapping the second bar-tacking portion S5, that is, the start end portion of the first parallel stitch portion S1 is also narrowed. With the stitch width, the possibility of thread breakage in the second bar-tacking portion S5 can be completely wiped out.

[Effects of the Invention] As described above, the present invention is directed to a buttonhole overedging cycle sewing machine in which parallel stitches are formed on both sides of the buttonhole and bar-tacking portions are formed on both ends of the buttonhole. , The seam width of at least the seam portion of the bar-tacking portion that overlaps with the bar-tacking portion that is formed first is made narrower than the seam width of the parallel seam portion. It is possible to prevent yarn breakage during the formation of the bartack portion without impairing the external appearance continuity with the eye portion, and it is possible to significantly improve the productivity.

[Brief description of drawings]

1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a side view of what is shown in FIG. 1, FIG. 3 is a partially enlarged perspective view of what is shown in FIG. 1, and FIG. FIG. 7 is a partially enlarged perspective view of the cam shown in FIG. 1, FIG. 5 is an enlarged side view of the cam shown in FIG. 1, and FIG. 6 is an explanatory plan view showing a stitch forming process according to the same embodiment. FIG. 8 is an explanatory plan view showing a state in which a zigzag stitch baseline is changed in a boring cycle sewing machine, and FIG. 8 is a plan view showing a stitch forming process in a conventional boring cycle sewing machine. 3 ... Main cam 27 ... Eccentric cam (oscillation mechanism) 21 ... Oscillation link (oscillation mechanism) 6 ... Oscillation width conversion cam (oscillation width conversion mechanism) 9 ... Oscillation width conversion arm ( Swing width conversion mechanism 8 …… Base line conversion arm (base line conversion mechanism) 7a, 7b …… Bar-tacking cam 6a2 …… Groove

Claims (1)

[Scope of utility model registration request] 1. A main cam that rotates in association with a sewing machine main shaft, and a swing mechanism that swings a needle that moves up and down in conjunction with the sewing machine main shaft in a direction orthogonal to the cloth transport direction in synchronization with the vertical movement. A swing width changing mechanism that changes the swing width of the needle by the needle bar swing mechanism, and a baseline conversion mechanism that changes the baseline that is the reference of the swing of the needle are provided, and are linked to the rotation of the main cam. The cloth is linearly reciprocated, and the base line conversion mechanism converts the base line into a rectangular shape, thereby forming bar-tacking stitches by the bar-tacking cams formed on the main cam at both ends of the button hole by zigzag stitching. In the buttonhole overedging cycle sewing machine as described above, the swing mechanism swings the eccentric cam around a predetermined swing fulcrum as the eccentric cam rotates in synchronization with the raising and lowering of the needle. It is composed of a swing link that swings The swing width conversion mechanism includes an annular swing width conversion cam protruding from one surface of the main cam, and the swing link that follows the cam surface of the swing width conversion cam according to the height of the cam surface. And a swing width converting arm that changes the swing width of the needle to change the size of the swing width of the needle, and a stitch that overlaps the bartack stitch on the cam surface of the swing width converting cam. When forming the seam of the portion, a portion which the swing width converting arm follows is provided with a groove portion formed from the end of the bartacking cam to be substantially lower than the cam surface of the swinging width converting cam by the length of the bartacking cam. A cycle sewing machine for buttonholing, characterized in that the bartacking portion is sewn with a sewing width smaller than that of parallel seams of button seams. "