JPS63225Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a positioning structure for a movable claw in an overlock sewing machine, and in particular, a fixed claw that sets the stitch width and a movable claw that is movable in the stitch width direction.
In an over-edge sewing machine, the movable claw is configured to be adjustable and includes a movable piece that is movable between a use position and a non-use position of the movable claw and in the stitching width direction. an engagement receptacle in which the first engagement part engages with a member that does not move in the switching movement direction of the movable piece to prevent excessive movement of the movable claw in the direction of the use position; and a stopper piece that engages with the second engaging portion to prevent the movable claw from moving excessively in the direction of the non-use position. To accurately return a movable claw and a movable piece to a use position from a non-use position by keeping the attachment state of a movable claw and a movable piece immovable even when the movable piece is moved.

The overedge sewing machine has a fixed claw formed integrally with the needle plate to set a narrow overedge width, and a movable claw that is separate from the needle plate and is arranged in parallel with the fixed claw to set a wide overedge width together with the fixed claw. The movable claw is
In some overedging machines, the movable pawl is configured to be movable between a use position where it is aligned with the fixed pawl and an unused position where it is not aligned with the fixed pawl. In such overedging machines, when the movable pawl returns from the unused position to the use position, the part that is integral with the movable pawl is brought into contact with the needle plate or a part that is integral with the movable pawl, forcibly preventing any further over-movement, thereby determining the position of the movable pawl relative to the fixed pawl.

However, the movable claw does not only move between the use position and the non-use position as described above;
In addition, for edge stitching machines that move in the stitching width direction in the use position, the movable claw can be moved from the non-use position to the use position while the movable claw is separated from the fixed claw in the stitching width direction. When moved to , the movable claw is separated from the fixed claw in the stitching width direction, so even if the movable claw reaches the use position,
The portion that is integral with the movable claw does not contact the throat plate or the portion that is integral therewith, or the contact is incomplete. In this case, the movable claw cannot completely contact the throat plate, etc. for determining the use position, so if the movable claw is moved to the use position with strong force, it may be forced to move further than that. The blocking function is impaired, the positioning of the use position becomes incomplete, and as a result, the distance between the fixed claw and the movable claw becomes incorrect, making it impossible to form the desired hem stitch. arise.

In addition, since the part that is integral with the movable claw is configured to be adjustable in the movable piece, when the movable claw is moved to an unused position with strong force, further movement is not forced. The blocking function moves the attachment state between the part that is integral with the movable claw and the movable piece, and as a result, when the movable claw is moved to the use position, the distance between the movable claw and the fixed claw is further deviated. , a problem arises in that it is not possible to form a predetermined overlock seam.

This invention was made to solve such conventional problems, and its purpose is to move the movable claw between the use position and the non-use position, and also to move in the overlocking width direction in the use position. The object of this invention is to accurately move and position the movable claw from a non-use position to a predetermined use position, regardless of the position of the movable claw in the stitching width direction. The object of the present invention is to keep the movable pawl fixed to the movable piece in the overedge sewing machine so that the movable pawl always returns to the use position in the correct attachment state.

The structure of this invention will be explained with reference to the symbols of the illustrated embodiments. This invention includes a fixed pawl 2 which is formed integrally with the throat plate 1 and which sets a narrow stitching width.
and a movable claw 3 separate from the throat plate 1 which is arranged in parallel with the fixed claw 2 and sets a wide stitching width with the fixed claw 2, and the movable claw 3 is connected to the fixed claw 2. between a use position where the fixed claws are lined up together with the fixed claw 2 to form a wide overlocking width, and a non-use position where the fixed claws are not lined up with the fixed claws 2 to form a narrow overlock width only with the fixed claws 2. The movable claw 3 is configured to be adjustable in a movable piece 6 that performs a switching movement for moving the movable claw 3, and this movable piece 6 has a wide width formed by the fixed claw 2 and the movable claw 3. The sewing needle is installed so as to be adjustable and movable in the sewing width direction in order to change and adjust the stitching width, and is operated in cooperation with a sewing needle that moves up and down and a looper that swings in synchronization with the sewing needle. Only the fixed claw 2 or the fixed claw 2 and the movable claw 3
In this over-edge sewing machine that forms over-edge stitches with an over-edge width, the movable piece 6 is provided with engaging portions 65 and 68, and a member (a presser foot) that does not move in the switching direction of the movable piece 6 is formed on the movable piece 6. In order to position the movable claw 3 in the use position when the movable claw 3 is moved from the non-use position to the use position, the first an engagement receiving part 66 that is engaged with the engagement part 65 to prevent excessive movement of the movable claw 3;
A stopper that is engaged by the second engaging portion 68 to prevent excessive movement of the movable claw 3 in order to position the movable claw 3 in the non-use position when the movable claw 3 is moved from the use position to the non-use position. The present invention relates to a positioning structure for a movable claw in an overlock sewing machine, which is characterized in that a piece 67 is formed respectively.

Next, this invention will be explained based on illustrated embodiments.

First, the configuration will be explained. Reference numeral 1 designates a throat plate, on the needle drop side thereof, a fixed pawl 2 extending in the direction of cloth feeding direction A is provided, and a movable pawl 3 oriented in the same direction is provided in parallel with the fixed pawl 2. A projecting portion 3a extending toward the upper side of the fixed claw 2 is integrally provided on the upper part of the movable claw 3. The overhanging portion 3a covers the upper surface of the fixed claw 2 when the stitching width formed by the fixed claw 2 and the movable claw 3 is small, and extends between the fixed claw 2 and the movable claw 3 when the stitching width is large. There is. Moving claw 3
A mounting block 4 is integrally connected to the rear end of the mounting block 4, and a movable piece 6 is fixed to the mounting block 4 with a bolt 5 and locked with a nut 5a.

The installation of the mounting block 4 and the moving piece 6 is as follows:
This is done by maintaining a state in which the movable claw 3 is in the operating position, with its projecting portion 3a properly covering the upper surface of the fixed claw 2. After installation, both are locked and fixed, so they always remain immovable. A second engaging portion 68 is formed at the lower end of the portion of the movable piece 6 to which the mounting block 4 integral with the movable claw 3 is attached.

Furthermore, a finger hook 7 is integrally formed at the rear end of the movable piece 6. A hole 10 for positioning is provided in the lower part of the movable piece 6. The moving piece 6 is attached to the left side surface of the knife holder 11 in the cloth feeding direction A. That is, the surface of the female holder 11 is formed with an oblique guide groove 12 whose upper end is forward in the cloth feeding direction A and whose lower end is rearward in the same direction A.
2, the movable piece 6 engages in a movable manner.

Furthermore, a press plate 13 is arranged on the surface of the movable piece 6 opposite to the female holder 11. Presser plate 1
3 is fixed to the female holder 11 with bolts 14 and 15, and holds the movable piece 6 so that it does not come off the guide groove 12. The presser plate 13 has
A leaf spring 17 is fixed by a bolt 16, a ball 19 is placed in a through hole 18, and the ball 19 is biased by the leaf spring 17 to press the ball 19 against the movable piece 6. The ball 19 engages with the hole 10 of the movable piece 6 when the movable piece 6 is raised, and positions the movable piece 6 at the raised position of the movable piece 6 (the use position of the movable claw 3 as described later).

A pin 51 is fixedly protruding from the movable piece 6 near the finger hook 7. The pin 51 also serves as the first engaging portion 65 of this invention, and protrudes leftward from the movable piece 6 with respect to the cloth feeding direction A. A fixed plate 53 fixed to the sewing machine body 28 with bolts 52 faces the tip of the pin 51, and a hole 54 is formed in the fixed plate 53 on the extension of the pin 51 when the movable piece 6 is in the raised position.
The rear end edge 55 of the fixed plate 53 faces the extension of the pin 51 when the movable piece 6 is in the lowered position. The length of the pin 51 is equal to the length of the protrusion 3a of the movable claw 3.
is overlapping the top surface of fixing claw 2, when pin 5
1 has a length to engage with the hole 54 or the rear edge 55, and when the protruding portion 3a is separated from the fixing claw 2, the pin 51 moves from the hole 54 or the rear edge 55 in the cloth feeding direction A. It has a length that leaves it to the right.
When all or part of the projecting portion 3a overlaps the upper surface of the fixing claw 2, the pin 51 is inserted into the hole 5.
4 or the rear end edge 55.

Further, the presser plate 13 is fixed to the knife holder 11 as described above, and therefore moves together with the knife holder 11 in the switching movement direction connecting the movable claw 3 between the use position and the non-use position. Constructs parts that do not. A pin 51 forming the first engaging portion 65 is provided at the lower end of the presser plate 13.
An engagement receiving portion 66 for engagement is formed.
When the movable claw 3 is in the use position, the pin 51 abuts against the engagement receiving portion 66 from below and the movable piece 6
When the pin 51 engages with the engagement receiving portion 66, the ball 1 is inserted into the hole 10 of the moving piece 6 as described above.
9 is engaged, and the lowering of the movable piece 6 is suppressed by the urging force of the leaf spring 17.

Also on the right side of the knife holder 11 in the cloth feeding direction A.
Similar to the guide groove 12, a mounting groove 20 is formed with an inclination of about 45 degrees, the upper end being forward in the cloth feeding direction A and the lower end being rearward in the same direction A, and the lower knife 21 engages with this groove 20. The lower knife 21 is pressed and fixed in the mounting groove 20 by a knife holder 23 that is fixed to the knife holder 11 with a bolt 22 . At this time, the right edge of the lower knife 21 and the right edge of the movable claw 3 are substantially on the same line in the cloth feeding direction A.

Further, on the upper side of the knife holder 11, a pointer 25 is attached by a bolt 24 in front of the position of a support means to be described later that supports the knife holder 11 on the sewing machine body 28.
is fixed, and the tip 25a of the pointer 25 faces the scale 26 of the needle plate 1. The pointer 25 is made of a leaf spring and is bent into a roughly L-shape in a plane, the base end of which is fixed to the female holder 11 as described above, and the bent part 25b and the tip 25a side of the needle plate from below. The pointer 25 is pressed upward against the lower surface of the throat plate 1, thereby urging the pointer 25 in the direction of pushing up the needle plate 1. The throat plate 1 is fixed to the sewing machine body 28 against the urging force of the pointer 25, and therefore, the bolt 24 portion of the scalpel holder 11 is urged downward by the reaction force of the pointer 25 against the throat plate 1. be done. Pointer 2 with bolt 24 for female holder 11
Since the fixed position of 5 is located in front of the position of the hand holding means, the scalpel holder 11 is urged downward by the pointer 25 in front of the position of the supporting means.

The scale 26 is displayed on an illuminated transparent plate 27 formed on the throat plate 1.
The tip 25a of the pointer 25 faces the bottom surface and indicates the scale 26 that indicates the current overlocking width dimension.

A metal bush 3 serving as a bearing is installed in a horizontal hole 29 in the sewing machine body 28 that is perpendicular to the cloth feeding direction A.
0 is fixed with a bolt, inside the bushing 30,
An operating shaft 31 passes through it rotatably. A collar 33 is fixed to the left end of the operating shaft 31 in the cloth feeding direction A with a bolt 32 in contact with the left end surface of the bush 30.
On the right end surface of the bush 30 in the same direction A, the operating shaft 31
A retaining ring 34 is attached to prevent the operating shaft 31 from coming off. A thread groove 35 is formed on the right side of the operating shaft 31 in the cloth feeding direction A from the bush 30, and is screwed into the female thread 36 of the female holder 11. A circular knob 37 is fixed to the right end of the operating shaft 31 on the right side of the female holder 11 with a bolt 38.
The surface of 7 is covered with a decorative board 39. The operating shaft 31 and the knob 37 are provided with concave and convex portions that fit into each other at their ends, so that the two always rotate together. A display 40 indicating the direction of rotation of the knob 37 is provided on the decorative board 39. Further, a compression coil spring 41 is fitted onto the operating shaft 31 between the knob 37 and the female holder 11 to constantly urge the female holder 11 to the left.

Further, in the sewing machine body 28, a tubular support shaft 43, which is adjustable and held by a holding bolt 43a, is movably passed through a hole 42 parallel to the hole 29. A collar 45 is fixed to the left end with a bolt 44, and a support shaft 43
This is used as a stopper against movement of the to the right. Further, a collar 62 is fixed to the right side of the support shaft 43 by a bolt 61, and serves as a stopper against leftward movement of the support shaft 43. And the support shaft 43
Thread groove 46 on the right end of retaining bolt 43a that holds
is screwed into the female thread 47 of the female holder 11. Thus, the knife holder 11 is supported by the operating shaft 31 and the support shaft 43 with respect to the sewing machine body 28. Therefore, the female holder 11 is fixed to the sewing machine body 28 mainly by the shafts 31 and 43 and the holding bolt 43a.
A support means is configured to support the structure.

In addition, in the figure, 48 is a sewing machine bed, and 67 is a stopper piece fixed to the female holder 11 by a bolt 49. A second engaging portion 68 on the lower surface of the bending portion formed at the top of the stopper piece 67 abuts against the stopper piece 67 to prevent the movable piece 6 and the movable claw 3 from moving excessively. Since the movable claw 3 does not come into contact with the engagement receiving portion 66 and the stopper piece 67 even if the movable piece 6 is moved with a strong force, the attached state of both 3 and 6 is always maintained correctly.

Reference numeral 50 denotes a knife receiving portion formed by a slope, which is provided on the needle drop side of the needle plate 1, rear of the fixed jaw 2, i.e., in front of the cloth feed direction A, and is set on the side edge of the guide groove 63 formed opposite the mounting groove 20 of the knife holder 11 on the cloth feed direction A side, and therefore, like the mounting groove 20, the guide groove 63 extends in an oblique direction with its upper end forward in the cloth feed direction A and its lower end rearward in the same direction A. Thus, the lower knife 21 is inserted between the mounting groove 20 of the knife holder 11 and the guide groove 63 of the needle plate 1.
By fitting both the lower knife 21 into the lower knife 22,
The lower tip of the blade of the lower knife 21 contacts the knife receiving portion 50, and the lower knife 21 is supported from below by this knife receiving portion 50. In the drawing, reference numeral 64 denotes an upper knife which moves up and down in the vertical direction to slide against the lower knife 21, and the material to be sewn is cut by both knives 21 and 64, and the edges thereof are trimmed evenly.

Next, the effect will be explained.

In this description, the front, back, top, bottom, left and right directions refer to a cloth feeding direction A, which is a traveling direction of a cloth showing a specific example of a sewing object. The overlocking width of the edge is determined by the width between the left side of the fixed claw 2 and the right side of the movable claw 3 in the use position (the position of the movable claw 3 shown by a solid line in FIG. 2). By moving the movable claw 3 in the left-right direction, the stitching width can be adjusted. This overlocking width adjustment is performed by rotating the knob 37. Fixed claw 2 and movable claw 3
The width of the overlock formed using the can be adjusted between 2.5 mm and 5.0 mm. That is, when the knob 37 is rotated to the right, the stitching width increases, and when the knob 37 is rotated to the left,
It can be understood from the display 40 of the knob 37 that the overlocking width becomes smaller.

Here, when the overlocking width is small, the movable claw 3
Since the projecting portion 3a overlaps the upper surface of the fixed claw 2, the fixed claw 2 and the movable claw 3 can be sufficiently close to each other. Further, when the stitching width is large, the overhanging portion 3a of the movable claw 3 protrudes toward the fixed claw 2 side, thereby narrowing the gap between the fixed claw 2 and the movable claw 3.
Therefore, during oversewing, the fabric is supported from below by the overhanging portion 3a between the fixed claw 2 and the movable claw 3, so that the fabric is prevented from falling between the two pieces 2 and 3. Ru.

Therefore, when the knob 37 is rotated in either direction, the operating shaft 31 rotates together with the knob 37, and the female holder 11, which is screwed into the thread groove 35 of the operating shaft 31, moves to the left or right. Operation axis 31
The retaining ring 34 and the collar 33 allow only rotational movement without axial movement. Then,
An operating shaft 31 that performs only rotational movement and its thread groove 3
5 and the female holder 11 screwed into the knob 3.
7 constitutes a means for converting the rotational force of the knife holder 11 into a force for moving the knife holder 11 forward and backward. Due to the movement of the knife holder 11, the support shaft 43 moves together with the knife holder 11, but when the knife holder 11 moves to the right, the collar 45 hits the sewing machine body 28 at the limit of movement, and the collar 45 hits the sewing machine body 28 to the right of the knife holder 11. Stop moving in that direction. Further, when the scalpel holder 11 moves to the left, the collar 62 hits the fixing plate 53 at the limit of movement, and the scalpel holder 1
1 stops moving to the left. Thus, the scalpel holder 11 is always supported by the sewing machine body 28 by the support means including the operation shaft 31, the support shaft 43, and the like.

Due to the movement of the knife holder 11, the movable piece 6 also moves to the left and right, so the movable claw 3 also moves in the same way, so that the stitching width can be adjusted. At this time, the pointer 25 also moves together with the knife holder 11, and the stitching width at that time is displayed on the scale 26. This movement of the pointer 25 is performed while the bent portion 25b and its front side are in sliding contact with the lower surface of the throat plate 1. Therefore, the bent portion 25b of the pointer 25 is maintained in pressure contact with the throat plate 1, so that the spring force of the pointer 25 constantly urges the scalpel holder 11 downward in front of the position of the support means. Thus, female holder 1
Since the front side of the knife holder 1 is always urged downward from the position of the support means, the front side of the scalpel holder 11 is suppressed from vertically vibrating due to sliding contact when the upper and lower knives 64 and 21 cross each other.

By the way, in this embodiment, in order to allow the left and right movement of the scalpel holder 11, the operation shaft 31 and the knife holder 11 are screwed together, and the screwed portion has a backlash, so that the scalpel holder 11 and the operation shaft 31 are screwed together.
cannot be rigidly connected. Furthermore, since a gap is provided between the holes 29 and 42 of the sewing machine body 28, and the operating shaft 31 and the tubular support shaft 43 that are inserted into the holes 29 and 42 to allow the left and right movement of the female holder 11, the sewing machine Female holder 1 for body 28
Mounting method 1 also does not have sufficient rigidity.

Therefore, since the pointer 25 made of a spring-like elastic body urges the front part of the knife holder 11 downward and presses it down, and the tip of the lower knife 21 is also seated on the knife receiving part 50 of the throat plate 1, the sewing machine body The vertical vibration of the female holder 11, which could not be rigidly connected to the female holder 28 as described above, was also suppressed.
Therefore, the lower knife 2 supported by the knife holder 11
1 and the movable claw 3 are also suppressed from vertically vibrating.

According to the inventor's experiment, in the case of this embodiment, when the pointer 25 made of a spring-like elastic body was not used, the vertical vibration of the lower scalpel 21 was 0.3 mm, but when the pointer 25 was used. In this example, the vibration was 0.007 to 0.013 mm. Vibrations with this level of amplitude do not cause any practical problems.
Furthermore, if the thickness of the pointer 25 is increased to increase its spring rigidity, the frictional force between the pointer 25 and the throat plate 1 becomes too large, impairing the smoothness of horizontal movement of the scalpel holder 11.

The female holder 11 also has a compression coil spring 41.
Since it is always biased to the left by the lever, even if the screwing of the operating shaft 31 and the female holder 11 occurs, the female holder 11 will not be left or right.

Furthermore, since the lower knife 21 also moves together with the movement of the knife holder 11, the lower knife 21
1 and the movable claw 3 do not change. Accordingly, the cutting position of the cloth also changes in accordance with the change in the stitching width. Further, since the lower tip of the blade of the lower knife 21 is supported from below by the knife receiving portion 50 of the throat plate 1, the load generated when cutting the cloth is applied not only to the supporting means of the knife holder 11 but also to the throat plate. It is also added to the knife receiving part 50 of No. 1, and is shared and supported by the knife holder 11 and the throat plate 1. Therefore, the magnitude of the load that is repeatedly applied to the support means for supporting the knife holder 11 to the sewing machine body 28 can be significantly reduced. Therefore, it is possible to prevent the support force of the support means from decreasing and also to prevent the members of the support portion from deforming, so that the lower knife 21 and the knife holder 11 are prevented from wobbling. There is no knob 3
The cloth cutting position can be easily and smoothly adjusted by the rotation operation in step 7.

Note that it is also possible to overedge using only the fixed claw 2 without using the movable claw 3. Since this is an edge stitching based only on the width dimension of the fixed claw 2, the edge stitching is extremely narrow. At this time, the movable claw 3 is moved backward and downward to a non-use position (the position of the movable claw 3 indicated by the chain line in FIG. 2). This movement is performed by first moving the moving claw 3 to the right.
The projecting piece 3a is separated from the upper surface of the fixing claw 2. This is done by moving the scalpel holder 11 to the right by rotating the knob 37 as described above.

As a result, the tip of the pin 51 of the movable piece 6 escapes from the hole 54 of the fixed plate 53, so that the movable piece 6 can freely move forward and backward. Therefore, the moving piece 6 is moved downward by hooking a finger on the finger hook 7 of the moving piece 6 and pulling it down. Then, the movable piece 6 descends along the guide groove 12, and the second engaging portion 68 of the portion where the mounting block 4, which is integrated with the movable claw 3, is fixed comes into contact with the stopper piece 67. The moving piece 6 and the moving claw 3 stop descending. This is the position shown by the chain line in FIG.
The movable piece 6 is also lowered to the unused position.
According to this embodiment, the stopper piece 67 is provided on the knife holder 11, but it may also be provided on a member that does not move between the use position and the non-use position, such as the fixing plate 53 or the sewing machine body 28. Of course.

Here, when performing the extremely fine overlocking, the knife holder 11 is moved to the left end by rotating the knob 37, and the lower knife 21 is brought closest to the throat plate 1. Thereby, the cloth cutting position is on the same line as the right edge of the fixed claw 2, making the overlock stitch extremely thin. Similarly, with the movable claw 3 in the unused position, the female holder 11 is rotated by rotating the knob 37.
When is moved to the right from the time of the ultra-fine hem stitching, although the stitching width is extremely thin, the cutting width of the cloth becomes wider, so that the fabric wraps around the fixed claw 2 and the hem is sewn. be done. This is the so-called overlock stitch. Thus, according to this embodiment, in addition to being able to adjust the overlock width, it is also possible to perform overlock stitching simply by rotating the knob 37 and moving the movable piece 6.

Note that when the knife holder 11 is moved to the left as described above in the position where the movable claw 3 is not used, the tip of the pin 51 of the movable piece 6 touches the rear edge 5 of the fixed plate 53.
Enter the back of 5. This makes it impossible for the movable piece 6 to move forward or backward in the same way as when the tip of the pin 51 enters the hole 54 of the fixed plate 53 as described above. That is, when the tip of the pin 51 is in such a state, the female holder 11 is closer to the left side, and the fixed claw 2 is positioned on the forward and backward trajectory of the overhanging portion 3a of the movable claw 3.
This is because if the movable piece 6 is moved back and forth as it is, the projecting portion 3a will interfere with the fixed claw 2. Therefore, in such a state, the movable piece 6 cannot move forward or backward, and the overhang 3a
Avoid interference between the and fixed claws 2, and hold both 3a, 2.
This is to prevent damage to the product. Therefore, pin 51
When the tip of the movable claw 3 and its protruding portion 3a move to the right side away from the hole 54 and the rear end edge 55, the movement trajectory of the movable claw 3 and its protruding portion 3a will be on the right side of the fixed claw 2, so that there is no possibility of the interference. Therefore, the movable piece 6 can be freely moved up and down, and the movable claw 3 can be advanced and retreated between the use position and the non-use position.

In order to return the movable claw 3 to the use position, the tip of the pin 51 is moved away from the hole 54 and the rear edge 55 to the right, and the finger hook 7 is pushed up.
As a result, the movable piece 6, the mounting block 4, and the movable claw 3 rise to the above-mentioned use position. At this time,
When the position of use is reached, the hole 10 of the moving piece 6 is aligned with the ball 1.
9, and the ball 19 falls into the hole 10, while the pin 51, which is the first engaging part 65, touches the presser plate 1.
3, and comes into contact with the engagement receiving portion 66 of No. 3. Here, the reason why the ball 19 falls into the hole 10 is due to the biasing force of the leaf spring 17, so even if you try to fix the position of the movable piece 6 only by this, the movable piece will be moved by the force that overcomes this biasing force. 6 is pushed up, the ball 19 is taken out from the hole 10, and the movable piece 6 is further pushed up. However, according to this embodiment, in the use position, the pin 51 comes into contact with the engagement receiving part 66 of the holding plate 13. Therefore, the moving piece 6 is forcibly prevented from moving any further. Therefore, even if the movable piece 6 is pushed up with a strong force, it will be forcibly stopped at the use position, and the movable claw 3 will also be correctly positioned at the use position.

In addition, according to this embodiment, the pin 51 forming a safety mechanism for preventing interference between the overhanging part 3a of the movable claw 3 and the fixed claw 2 is also used as the first engaging part 65; The first engaging portion 65 may be provided separately from the pin 51 on the movable piece 6 or on a member that moves integrally therewith. In addition, the engagement receiving portion 66 is
3 other members, i.e., the fixing plate 53 and the sewing machine body 2
Of course, it may be provided on a member that does not move between the use position and the non-use position, as shown in 8.

As explained above, in this invention, the movable piece is formed with the first and second engaging parts, and the member that does not move in the switching direction of the movable piece is moved along the switching locus of the movable piece. an engagement receptacle in which the first engaging portion engages to position the movable claw in the use position when the movable claw is moved from the non-use position to the use position, thereby preventing excessive movement of the movable claw; and a stopper piece that is engaged by the second engaging portion to prevent excessive movement of the movable claw in order to position the movable claw in the non-use position when the movable claw is moved from the use position to the non-use position. and were formed respectively. Therefore, even when the movable claw is moved from the non-use position to the use position with strong force, the first engagement part is forcibly blocked by the engagement receiving part, so the movable claw is moved to the use position. be positioned securely.

Furthermore, even when the movable claw is moved from the use position to the non-use position with strong force, the second engaging portion comes into contact with the stopper piece, so that excessive movement of the movable claw is prevented, and The state of attachment to the moving piece is always maintained correctly. Therefore, the overlocking width formed by the movable claw and the fixed claw is always set to a predetermined width at an accurate position, so that it is possible to perform beautiful overlocking with uniform seams.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of this invention;
FIG. 2 is a right side view of FIG. 1, FIG. 3 is a sectional view taken along line B-B in FIG. 2, FIG. 4 is a sectional view taken along line C-C in FIG. 3, and FIG. FIG. 4 is a sectional view taken along the line DD, FIG. 6 is a view taken in the direction of arrow E in FIG. 4, and FIG. 7 is an exploded perspective view. A... Cloth feeding direction, 1... Throat plate, 2... Fixed claw, 3... Moving claw, 6... Moving piece, 11... Knife holder (portion that does not move), 13... Presser plate (portion that does not move) ), 65...first engaging portion, 66...
...Engagement receiving part, 67...Stopper piece, 68...Second engagement part.

Claims (1)

[Scope of utility model registration request] A fixed pawl that is formed integrally with the throat plate and sets a narrow stitching width, and a movable pawl that is separate from the throat plate and is provided in parallel with the fixed pawl and sets a wide stitching width with the fixed pawl. and a use position in which the movable claw is lined up with the fixed claw to form a wide overlocking width together with the fixed claw, and a use position where the movable claw is not aligned with the fixed claw so as to form a narrow overlocking width with only the fixed claw. The movable claw is configured to be adjustable in a movable piece that switches between a non-use position and a non-use position to move the movable claw, and the movable piece is formed of the fixed claw and the movable claw. It is installed so that it can be adjusted and moved in the direction of the stitching width in order to change and adjust the thick stitching width. In the hem sewing machine that forms an overseam seam having a hem width consisting of only the fixed claw or both the fixed claw and the movable claw, the movable piece has first and second engaging portions. and for positioning the movable claw in the use position when the movable claw is moved from the non-use position to the use position at a position along the switching locus of the movable piece of a member that does not move in the switching movement direction of the movable piece. an engagement receiving part that is engaged by the first engagement part to prevent over-movement of the movable claw; and an engagement receiving part that positions the movable claw in the non-use position when the movable claw is moved from the use position to the non-use position. A positioning structure for a movable pawl in an overcut sewing machine, characterized in that a stopper piece is formed, which is engaged by the second engaging portion to prevent over-movement of the movable pawl.