JP2003117278A - Stitching method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform sewing not to make stitch thread appear on a surface of a sewing material when putting the surfaces of two sewing materials together, sewing the ends, then turning the sewn part to an inner side and splitting open the sewing materials in a thick leather material such as an automobile seat or furniture. SOLUTION: By a cloth feeder for a sewing machine forming stitches, the stitches are successively formed on cloth by repeating processings of forming a plurality of the stitches by feeding the cloth in one direction for n+1 stitches or more and then forming the stitches by feeding it in the opposite direction for n stitches by the same feed amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine stitch forming method and device, and more particularly, in sewing thick leather materials such as automobile seats and furniture, the two sewing materials are brought into front-to-back stitching at their ends. The present invention relates to a method and a device for forming a stitch of a sewing material in which the sewing material is split and opened for use later.

[0002]

2. Description of the Related Art Conventionally, generally, as shown in FIG. 6, first, the upper cloth W1 and the lower cloth W2 are aligned. The upper cloth end and the lower cloth end are sewn together by a sewing machine that forms a main stitch by cooperation of a needle and a shuttle. As a result, the ends of the two upper cloths W1 and lower cloths W2 form a full stitch by the upper thread NS and the lower thread US as shown in FIG. After that, as shown in FIG. 8, the upper cloth W1 and the lower cloth W2 are used with the sewn portion being inwardly opened.

[0003]

However, as shown in FIG.
The strength of the fastening force of the sewn portion sewn as shown in FIG. 7 is the tensile strength of each of the upper thread NS and the lower thread US and the upper thread N.
The frictional force at the node between S and the lower thread US, the upper thread W1 and the upper thread NS across the front and back of the lower cloth W2, and the lower thread US and the upper cloth W1,
It is determined by the frictional force generated between the lower cloth W2.
Therefore, the strength of the fastening force at these sewn portions is applied to one thread, and depends on the strength of a single thread.

When the sutured portion is split open, the upper thread NS and the lower thread US are stretched, the knot points of the upper thread NS and the lower thread US are deformed, the upper thread NS and the lower thread US and the upper cloth W1, The upper cloth W1 and the lower cloth W2 are compressed at the contact portion with the cloth W2.

As a result, when the stitching portion is opened, the upper cloth W
1. The contact surface at the stitching portion of the lower cloth W2 opens, and as shown in FIG. 8, the upper thread NS, the lower thread US, or the knot points of both appear on the table of the upper cloth W1 and the lower cloth W2, which lowers the commercial value. There is a problem that causes

Further, in order to increase the knotting force of the upper thread NS and the lower thread US, the thickness of the upper thread NS and the lower thread US is increased and the tension between the upper thread NS and the lower thread US is increased. It is possible to do it.

However, in the lockstitch sewing machine, a knot is formed in the central portion between the upper cloth and the lower cloth due to the balance of tension between the upper thread NS and the lower thread US. Since the means for applying tension to the thin leaf spring is a thin leaf spring, there is a limit to increasing the tension of the lower thread US due to its structure, and as a result, a large tension is applied to the upper thread NS and the lower thread US. However, there is a limit to remarkably increasing the knotting force of the upper thread NS and the lower thread US.

Even if the tension is increased and the stitches are sewn as described above, the elongation of the upper thread NS and the lower thread US, and the upper thread N
Deformation of node between S and bobbin thread US, upper thread NS and bobbin thread US
It is impossible to completely prevent the upper cloth W1 and the lower cloth W2 from being compressed at the contact portions between the sewing cloths W1 and W2. Therefore, when an impact is applied to the portion where the stitched portion is split open, as shown in FIG. 8, the upper thread NS, the lower thread US, or the knot points of both appear on the table of the upper cloth W1 and the lower cloth W2, and the commercial value There is a problem that lowers.

Even if the fastening force is improved by a chain stitch made of a combination of a plurality of threads, such as a double chain stitch or a flat stitch, these chain stitches will be unraveled if a part of the thread is cut. There is a problem with durability.

Further, the conventional stitched portion is sewn once,
It is conceivable that the strength of the fastening force should be increased by overlapping the stitch thread and re-sewn. However, this requires that the upper cloth and the lower cloth be returned to the sewing start position again after sewing once. Since it does not occur, it is difficult to work efficiently, it is difficult to pierce the needle at the same position of the seam that was sewn in front, and it is not possible to prevent deformation of the knot point between the upper thread NS and the lower thread US. There's a problem.

Further, as shown in FIG. 9, it is conceivable that the upper cloth W1 and the lower cloth W2 are sewn by hand by two threads HS1 and HS2, but it takes a lot of time to form the stitches. However, there is a problem in that the sewing work efficiency is reduced and the length of the thread is limited, so that a long stitch cannot be formed.

[0012]

In order to solve the above-mentioned conventional problems, the invention of claim 1 uses a sewing machine for forming a main stitch, and a cloth feeding device moves the cloth in one direction (n + 1) needles. Forming a plurality of stitches by feeding, then repeatedly feeding n stitches in the opposite direction to one direction with the same feed amount to form stitches repeatedly, forming stitches continuously on the fabric. Is the way.

According to the invention described in claim 1, 1
Since the upper cloth and the lower cloth sewn with the main stitches that are thread-fastened for each needle form a plurality of knot points at each stitching point, the tensile strength of each of the upper thread NS and the lower thread US is increased. The upper thread NS and the lower thread U at each stitching point
The frictional force at the node with S also increases.

Further, since a plurality of upper threads NS and lower threads US cross the front and back of the upper cloth W1 and the lower cloth W2, between the upper thread NS and the lower thread US and the upper cloth W1 and the lower cloth W2. Large frictional force is generated.

Further, the strength of the fastening force is dispersed in the plurality of yarns.

From the above, when the suture portion is split open, the elongation of the upper thread NS and the lower thread US decreases and the upper thread N
The deformation of the node between S and the bobbin thread US is reduced, and the upper thread N
The compression of the upper cloth W1 and the lower cloth W2 at the contact portion between the S and the lower thread US and the upper cloth W1 and the lower cloth W2 is also extremely small.

Therefore, when the stitched portion is opened, the upper cloth W is
1. The contact surface of the lower cloth W2 at the stitched portion is prevented from opening. Further, even if an impact is applied to the portion where the sewn portion is split and opened, the upper thread NS, the lower thread US, or the knot points of both of them do not appear on the surface of the upper cloth W1 and the lower cloth W2, so that the shock resistance is excellent. , The product value of the product is improved.

Even if a part of the seam is cut,
Since it is a lock seam, it does not fray from the part and has an effect of excellent durability.

Further, in this sewing method, since continuous sewing is possible, there is an effect that the sewing work efficiency is improved.

Further, since the needle can be stabbed at the same position of the seam previously sewn and deformation of the knot point between the upper thread NS and the lower thread US can be prevented, the quality of the product is improved. The effect that the commercial value of the sewn product is improved can be obtained.

According to a second aspect of the invention, in the stitch forming method according to the first aspect, after sewing two stitches of cloth in one direction, one stitch is sewn in a direction opposite to one direction to form a stitch of a sewing machine. Is the way.

The invention described in claim 2 can more reliably achieve the effect described in claim 1.

According to the third aspect of the present invention, the cloth feeding device feeds the cloth 2n needles in one direction to form a plurality of stitches with respect to the sewing machine forming the main stitch, and then the one feed direction is defined as one direction. This is a stitch forming method for a sewing machine in which the stitches are continuously formed by feeding n stitches in the opposite direction to continuously form the stitches on the cloth.

According to the invention described in claim 3, the same effect as the effect described in claim 1 can be obtained.

According to a fourth aspect of the present invention, in the stitch forming method according to the first, second and third aspects, at least one or more hitch stitches are formed at each stitched portion of the sewing machine.

In the invention of claim 4, since a hitch stitch having a strong knotting force is formed at each stitching point, the effect described in claim 1 can be further improved.

According to a fifth aspect of the present invention, the sewing machine that forms the lock stitch, the cloth feeding device that feeds the cloth in one direction and the direction opposite to the one direction, and the cloth feeding device feeds n + 1 needles in one direction. later,
A stitch forming device for a sewing machine, which is provided with a control means for continuously controlling the cloth feeding device so as to feed n needles in a direction opposite to one direction by the same feed amount.

In the invention of claim 5, the same effect as the effect described in claim 1 can be obtained.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram of a control circuit as a control means in the present invention. Reference numeral 1 is a start switch of a sewing machine arranged on a foot pedal, and when the foot pedal is stepped on the toe, a command to start the sewing machine is issued and the foot petal. By returning the sewing machine to the original position, a command to stop the sewing machine is issued to the control device described later. Reference numeral 2 denotes a needle position detector provided on a main shaft of a sewing machine, which will be described later, detects the vertical position of the needle, and counts the number of needles by a counter 4 in a control device CPU 3 as a control means. The needle position detector 2 and the counter 4 constitute a needle number detecting means. 5 is a sewing machine motor for driving the sewing machine, 6 is a feed amount setter, which sets the stroke of an actuator of a direct drive motor, which will be described later.
Is a feed direction setter, which selects the protruding position or the retracted position of the actuator of the linear motion motor 16 described later, and selects one of the cloth feeding directions (one direction (hereinafter, referred to as positive direction)) and one direction (hereinafter, referred to as a positive direction). The opposite direction) and to convert.

The sewing machine motor 5, the feed amount setter 6, the feed direction converter 7 and the like are driven via the drive unit 8 in response to a command from the control unit CPU3 as a control means having a memory. The circuit is configured.

FIG. 2 shows an example of the cloth feeding device 29, which is a mechanism diagram of a cloth feeding mechanism of a known sewing machine in principle.
Is a main shaft of the sewing machine, and 10 is an eccentric cam provided on the main shaft 9. Reference numeral 11 is a cloth feed direction changer, the center of which is rotatably supported by a shaft 12 on a bed of a sewing machine (not shown). At the left end of the feed direction changer 11, the bases of the two links 13 and 14 having the same length are coaxial shafts 13.
These links 1 are rotatably supported by A and 14A.
The tips of 3 and 14 are connected by a common shaft 15. 16
Is a linear motion motor fixed to a sewing machine frame (not shown), and its actuator 17 and the right end of the feed direction changer 11 are rotatably connected by a link 18.
Reference numeral 19 is a vertical link, the upper end of which is connected to the eccentric cam 10 and the lower end of which is rotatably connected to the shaft 15 at the tips of the links 13 and 14.

Reference numeral 20 denotes a horizontal feed shaft rotatably supported on a bed of a sewing machine (not shown). The lower end of an arm 21 projecting upward is fixed to the right end of the horizontal feed shaft 20, and the upper end is raised to the left end. The lower end of the protruding arm 22 is fixed. Reference numeral 23 is a connecting link, one end of which is rotatably connected to the shaft 15 at the tip of the links 13 and 14, and the other end of which is rotatably connected to the tip of the arm 21. Reference numeral 24 denotes a cloth feeding arm, one end of which is rotatable on the tip of the arm 22, and the other end of the forked portion 25 is loosely fitted to a vertical cam 27 provided on a vertical movement shaft 26. Reference numeral 28 is a cloth feed tooth fixed to the cloth feed arm 24.

In the cloth feeding mechanism 29 as the cloth feeding device shown in FIG. 2 described above, when the sewing machine drives the main shaft 9 to rotate, the vertical link 19 moves up and down by the eccentric cam 10, whereby the shaft 15 at the lower end is moved. Move up and down a certain amount.

The vertical movement of the shaft 15 is transmitted to the horizontal feed shaft 20 in the following manner to determine the cloth feed amount and cloth feed direction of the cloth feed teeth 28.

That is, when the vertical movement position of the shaft 15 is at the intermediate position, the shafts 13A and 14A move toward the upper end of the arm 21 and the shaft 15.
When the vertical link 19 moves the shaft 15 up and down, the links 13 and 14 are connected to the shaft 13A,
The cloth feed dog 28 is stationary, and the cloth is not fed.

When the vertical movement position of the shaft 15 is at the intermediate position and the shafts 13A and 14A are above the straight line connecting the upper end of the arm 21 and the shaft 15, the vertical link 19 moves the shaft 15 up and down. When moved, the links 13, 14 will move the shaft 13
It swings around A and 14A. This allows the cloth feed dog 28
Feeds the cloth in the forward feeding direction, which is one direction, while protruding from the upper surface of the needle plate (not shown). The cloth feed amount in the forward feed direction increases as the positions of the shafts 13A and 14A move upward with respect to the straight line connecting the upper end of the arm 21 and the shaft 15.

When the vertical movement position of the shaft 15 is at the intermediate position and the shafts 13A and 14A are below the straight line connecting the upper end of the arm 21 and the shaft 15, the vertical link 19 moves the shaft 15 up and down. When moved, the links 13, 14 will move the shaft 13
It swings around A and 14A. This allows the cloth feed dog 28
Feeds the cloth in the reverse feeding direction opposite to the one direction while protruding from the upper surface of the needle plate (not shown). And shafts 13A, 1
The amount of cloth feeding in the reverse feeding direction increases as the position of 4A moves downward with respect to the straight line connecting the upper end of the arm 21 and the shaft 15.

From these facts, the cloth feed direction and the cloth feed amount in the forward and reverse directions are determined by the positions of the shafts 13A and 14A at the tips of the links 13 and 14, and the tips of the tips of the links 13 and 14 are determined. The positions of the shafts 13A and 14A are controlled by the linear motion motor 16 shown in FIG.

That is, when the actuator 17 of the linear motion motor 16 rises to the retracted position, the fabric feed converter 11 rotates counterclockwise about the shaft 12 and stops, whereby the positions of the shafts 13A and 14A are changed. Is determined, and the forward feed direction and the feed amount as one direction are determined by the retracted position of the actuator 17.

Further, the actuator 1 of the direct drive motor 16
When 7 descends and reaches the projecting position, the cloth feed converter 11 moves to the shaft 1
It rotates clockwise about 2 and stops, so that shaft 1
The positions of 3A and 14A are determined, and this actuator 1
The protruding position of 7 determines the reverse feed direction and the feed amount in the opposite direction to the one direction.

In other words, the cloth feed direction and the cloth feed amount are determined by the retracted position and the projected position of the actuator 17 of the linear motion motor 16, and these positions are set by the feed amount setting device 6 of FIG.

The linear motor 16 is driven by a signal from the feed direction setting device 7 shown in FIG.

Next, the operation of the first embodiment of the present invention will be described. The first embodiment is an example in which (n + 1) needles are sewn in the forward feed direction and n needles are sewn in the reverse feed direction (n is an arbitrary natural number). The first embodiment is the case where n = 1.

First, by the feed amount setting device 6, the retracted position and the projected position of the actuator 17 of the linear motion motor 16,
Set so that the cloth feed amount is the same in the forward and reverse feed directions.

Next, the feed direction setter 7 counts the number of stitches of the needle position detector 2 by the counter 4, and the actuator 17 of the linear motion motor 16 is set to the retracted position while the needle is being dropped twice. The stitches are formed by maintaining the forward direction as one direction, and then the actuator 17 of the linear motion motor 16 is set as the projecting position to maintain the cloth feed direction in the opposite direction to the one direction and once It is set to repeat dropping and forming a stitch continuously. In other words, after feeding the cloth in the two needles in the forward direction, feeding the cloth in the reverse direction by one stitch at the same cloth feed amount as the forward direction is continuously repeated, and the cloths are set to be fed.

After the cloth feed direction and cloth feed amount are set as described above, when the start switch 1 is turned on by the foot pedal of FIG. 1, the sewing machine motor 5 is driven and the stitches as shown in FIG. 3 are continuously formed. The order in which the stitches are formed will be described with reference to FIG.

In the stitch shown in FIG. 3, the upper threads NS1, NS2 and NS3 and the lower threads US1, US2 and US are used.
3 is vertically separated from the upper surface and the lower surface of the upper cloth W1 and the lower cloth W2, but in reality, the upper thread and the lower thread are tightly tightened for each stitch. It strongly adheres to the upper and lower surfaces of the cloth W1 and the lower cloth W2.

At the same time when the sewing machine motor 5 is driven, FIG.
The actuator 17 of the linear motion motor 16 shown in (4) is maintained at the lower protruding position to cause the cloth feed converter 11 to feed in the forward direction.

In this state, first, the needle of the first stitch drops to the stitching point A in FIG. 3 to form the perfect stitch knot 1A, and then the upper cloth W1 and the lower cloth W2 are moved in the forward direction of arrow X. One pitch P is fed, and the second needle falls to the suture point B to form a perfect stitch knot 2A.

The counter number of the two needles in the positive direction is 4
When the count is counted by the feed direction setter 7, a signal is generated from the feed direction setting device 7, the actuator 17 of the linear motion motor 16 is in the upper retracted position, the cloth feed converter 11 is in the reverse feed direction, and the upper cloth W1 and the lower cloth are W2 and W2 are fed by one pitch P in the reverse feed direction of the arrow Y direction, and the needle of the third needle falls to the suture point A to form the hitch stitch knot 3A.

When the counter 4 counts the number of one stitch in the reverse feed direction, a signal is generated from the feed direction setting device 7, and the actuator 17 of the linear motion motor 16 is in the downward protruding position. , The cloth feed converter 11 becomes the forward feed direction, the upper cloth W1 and the lower cloth W2 are fed by one pitch P in the forward feed direction of the arrow X direction, the needle of the fourth stitch falls to the sewing point B, and the perfect stitch A nodule 4A is formed. Further, the upper cloth W1 and the lower cloth W2 are fed by one pitch P in the forward feed direction, and the needle of the fifth stitch falls to the suture point C to form a perfect stitch knot 5A.

The number of the two stitches in the positive direction is the counter 4
When the count is counted by the feed direction setter 7, a signal is generated from the feed direction setting device 7, the actuator 17 of the linear motion motor 16 is in the upper retracted position, the cloth feed converter 11 is in the reverse feed direction, and the upper cloth W1 and the lower cloth are W2 and W2 are fed one pitch P in the reverse feed direction of the arrow Y direction, and the sixth needle falls to the suture point B to form a hitch stitch knot 6A.

In this way, two stitches are fed in the positive direction of the arrow X direction to form a stitch, and then one stitch is fed in the opposite direction of the arrow Y direction to form a stitch. To form such seams.

Therefore, in this stitch, as shown by the stitching points B and C in FIG. 3, two perfect stitches at one stitching point (same needle drop position) and one hitch stitch having a strong knotting force. And are formed. In addition, the three upper thread N on the upper surface of the upper cloth W1 during one pitch of cloth feeding.
S1, NS2, NS3 are present, and 3 is also on the lower surface of the lower cloth W2.
The lower threads US1, US2, and US3 of the book are respectively present to increase the frictional force at the contact surfaces between the upper thread and the upper cloth W1 and between the lower thread and the lower cloth W2.

After sewn with the stitches as shown in FIG. 3, even if the sewn portion is split open as shown in FIG. 4, the upper cloth W1,
The contact surface at the stitched portion of the lower cloth W2 does not open.

In the first embodiment, the first backtack was not performed, but the first backtack may be performed in response to an operator's operation signal.

For example, a portion which is fed to the stitch point A at the same interval (pitch) in the X direction is set as the stitch point Z (not shown). As the backtack at the start of sewing, after forming the stitch by dropping the needle at the stitching point Z, the stitch is formed at the 1-pitch feed stitching point A in the forward feed direction, and further the 1-pitch feed stitching is performed in the reverse feed direction. Form a seam at point Z. Then, after finishing the first stop stitch, the seam of the first embodiment is formed.

Further, in the first embodiment, the end stop stitch may be performed. For example, in the first embodiment, sewing ends one stitch before the final stitching point. afterwards,
As the final stop stitch, the cloth is fed at the same pitch in the forward feed direction X to form a perfect stitch at the final stitching point. In this manner, when the final stop stitch is performed, a plurality of knot points are formed at the final stitching point, so that the strength of the stitch is further improved. In addition, the execution of the first backtack and the final backtack is set by a signal input to the sewing machine controller, such as a DIP switch, and automatically executed by the start signal and end signal of the foot pedal. Is also easily conceivable.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment uses 2n in the forward feed direction.
It is a specific example of needle stitching and n needle stitching in the reverse feed direction (n is an arbitrary natural number).

In the seam shown in FIG. 5, the upper thread NS
1, NS2, NS3 and the lower threads US1, US2, US3 are vertically separated from the upper surface and the lower surface of the upper cloth W1 and the lower cloth W2, but in reality, the threads are tightly tightened for each stitch. Therefore, the upper thread and the lower thread strongly adhere to the upper surface and the lower surface of the upper cloth W1 and the lower cloth W2.

The same components as those in the first embodiment are designated by the same reference numerals in the drawings and their detailed description will be omitted.

In the second embodiment, the number of stitches in the forward feed direction and the reverse feed direction in the first embodiment is changed, and in the second embodiment, four stitches are fed in the forward feed direction. After that, the feed direction setting device 7 is set so that the stitches are formed by repeatedly feeding two stitches in the opposite direction.

When the sewing machine is driven by this, the suture points A, B, and
Perfect stitches 1A, 2A, 3A, 4A on C and D
After forming, 2 by feeding the cloth in the direction opposite to the arrow Y direction
Hitch stitches 5A and 6A are formed at the suture points C and B with a needle.

In this way, the stitches are formed by feeding 4 stitches in the forward direction and then the stitches are formed by feeding 2 stitches in the opposite direction, and the stitches as shown in FIG. 5 are formed.

Therefore, in this stitch, as shown by the stitching points B and C in FIG. 5, two perfect stitches at one stitching point (same needle drop position) and one hitch stitch having a strong knotting force. And are formed. In addition, the three upper thread N on the upper surface of the upper cloth W1 during one pitch of cloth feeding.
S1, NS2, NS3 are present, and 3 is also on the lower surface of the lower cloth W2.
The lower threads US1, US2, and US3 of the book are respectively present to increase the frictional force at the contact surfaces between the upper thread and the upper cloth W1 and between the lower thread and the lower cloth W2.

After the stitches are sewn with the stitches as shown in FIG. 5, the upper cloth W1,
The contact surface at the stitched portion of the lower cloth W2 does not open. In FIG. 5, a plurality of knot points are formed at the stitching point A and at the stitching point Z which is one pitch before the A direction in the X direction, but this is because the operator has operated the first stop stitch. . The first settling stitch is performed by forming a stitch at the stitching point Z, then feeding the cloth 1 pitch forward by the feeding device to form the stitch at the stitching point A, and then backward feeding 1 pitch for stitching. This is an operation of forming a stitch at the point Z and then forward feeding one pitch forward to form the stitch at the stitch point A. After that, the operation of the second embodiment is performed. Further, in the second embodiment, the final stop stitch may be performed. After the stitch formation is completed two stitches before the final stitching point, two stitches are performed by forward feed as a final stop stitching process. When this final stop stitch is performed, a plurality of knot points are formed at the final stitch point, so that the strength of the stitch is further improved.

In the above-described embodiment, the forward feed is 2
An embodiment in which one needle is sewn by reverse feed after needle suturing is repeated, and an embodiment in which four needles are sewn by forward feed and then two needles are sewn by reverse feed are described, but the following embodiment is considered. To be

That is, stitching with (n + 1) needles in forward feed and then stitching with n needles in reverse feed may be repeated (n.
Is any natural number). At this time, similarly to the first embodiment, it is preferable to perform the first tacking step and the end tacking step. This final stop stitching step is a step of stitching (one direction) n needles in a forward feed after the end of repeated sewing. By this stop stitch at the end, a plurality of knot points are formed at the final stitching point, so that the strength of the stitch is further improved.
Further, it is also possible to repeat stitching (2n) needles in the forward feed and then stitching n needles in the reverse feed (n is an arbitrary natural number).
At this time, similarly to the first embodiment, it is preferable to perform the first tacking step and the end tacking step.
This first stop stitching step may be a step of stitching with n needles at the forward feed at the start of sewing and then stitching with n needles at the reverse feed. Also,
The final backtacking step is a step in which, after the repeated sewing is completed, n needles are sewn in the forward feed (one direction). By this stop stitch at the end, a plurality of knot points are formed at the final stitching point, so that the strength of the stitch is further improved.

In the above-described embodiment, the number of needles to be sewn in the forward feed is larger than the number of needles to be sewn in the reverse feed, but the number of needles to be sewn in the reverse feed is opposite to this. May be larger than the number of needles to be sutured by forward feeding.

Further, in the above-described embodiment, the structure in which the upper cloth and the lower cloth are fed by the cloth feeding mechanism of the sewing machine has been described as the cloth feeding apparatus, but this cloth feeding apparatus is a well-known XY feeding apparatus. You may change to. As a result, it is possible to continuously form not only straight stitches, but also stitches of any shape such as curved stitches and stitches in which curved and straight lines are continuous.

The upper thread NS and the lower thread U at each stitching point
For the knot with S, a hitch stitch can be arbitrarily formed by controlling the upper thread NS, the lower thread US, the needle and the like. Further, in the above-described embodiment, a well-known hitch stitch preventing mechanism, for example, a mechanism that rotates the needle bar and the hook in the axial direction to prevent the formation of stitches in the hitch stitch forming feed direction region, is used. It is also possible to prevent the formation of a hitch stitch at the stitching point. If the hitch stitch preventing mechanism is not used, a hitch stitch is formed in the case of reverse feed. Therefore, a stitch that repeats normal feed (n + 1) stitches and then reverse feed stitches with n needles or a stitch that repeats forward feed (2n) needle stitches and reverse feed stitches with n needles is Since at least one hitch stitch is formed at each stitching point, the stitch has a strong knotting force at the stitching point.

[0073]

As described above, according to the present invention, since the upper cloth and the lower cloth sewn with the main stitches which are thread-fastened for each needle, a plurality of knot points are formed at each stitching point, Thread NS
The respective tensile strengths of the lower thread US and the lower thread US increase, and the frictional force at the knot point between the upper thread NS and the lower thread US at each stitching point also increases.

Further, since a plurality of upper threads NS and lower threads US cross the front and back of the upper cloth W1 and the lower cloth W2, between the upper thread NS and the lower thread US and the upper cloth W1 and the lower cloth W2. Large frictional force is generated.

Further, the strength of the fastening force is dispersed in the plurality of yarns.

From the above, when the suture portion is split open, the elongation of the upper thread NS and the lower thread US is reduced and the upper thread N is
The deformation of the node between S and the bobbin thread US is reduced, and the upper thread N
The compression of the upper cloth W1 and the lower cloth W2 at the contact portion between the S and the lower thread US and the upper cloth W1 and the lower cloth W2 is also extremely small.

According to the present invention, this prevents the contact surfaces of the upper cloth W1 and the lower cloth W2 from opening at the stitching portion when the stitched portion is split open, and the knot with the upper thread NS, the lower thread US, or both. Since the dots do not appear on the surface of the upper cloth W1 and the lower cloth W2, the product value of the product is improved and the upper thread NS, the lower thread US, and the both of the upper thread NS and the lower thread US can be obtained even if an impact is applied to the part where the sewn portion is split and opened. The knot points of and do not appear on the surface of the upper cloth W1 and the lower cloth W2, and there is an effect of excellent impact resistance.

Even if a part of the thread of the seam is cut, since it is the main seam, it is not frayed from the part, and the durability is excellent.

Further, in this sewing method, since it is possible to continuously sew, there is an effect that the sewing work efficiency is improved.

Further, since the needle can be stabbed at the same position of the seam stitched before, and the deformation of the knot point between the upper thread NS and the lower thread US can be prevented, the product quality is improved. The effect that the commercial value of the sewn product is improved can be obtained.

Furthermore, since a hitch stitch having a strong knotting force is formed at each stitching point, the effect described above can be further improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a control circuit of the present invention.

FIG. 2 is a cloth feed mechanism diagram of a sewing machine as an example of the cloth feed device of the present invention.

FIG. 3 is a seam according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing a state in which the stitching portion of the cloth stitched with the stitches of the present invention is split open.

FIG. 5 is a seam according to a second embodiment of the present invention.

FIG. 6 is a perspective view of a conventional seam.

FIG. 7 is a sectional view taken along line VV of FIG.

FIG. 8 is a perspective view of the sewn article of FIG. 6 in a state in which it is split open from the stitching portion.

FIG. 9 is a cross-sectional view of another conventional seam.

[Explanation of symbols]

3 Control device (control means) 6 Feed amount setting device 7 Feed direction setting device (cloth feed device) 11 Feed direction changer (cloth feed device) 16 Linear motor 29 Cloth feeding device

Claims (5)

[Claims] 1. A cloth feed device feeds the cloth in one direction (n + 1) needles to form a plurality of stitches with respect to a sewing machine that forms a main stitch, and then the same feed amount is applied in a direction opposite to the one direction. A stitch forming method for a sewing machine, wherein the stitches are continuously formed by feeding n stitches to the fabric to form the stitches continuously. 2. The stitch forming method according to claim 1, wherein two stitches of the fabric are sewn in one direction, and then one stitch is sewn in a direction opposite to the one direction to continuously form the stitches in the fabric. A method for forming a seam on a sewing machine, comprising: 3. A fabric feeding device feeds 2n needles in one direction to form a plurality of stitches with respect to a sewing machine forming a main stitch, and then n is fed in a direction opposite to the one direction by the same feed amount. A stitch forming method for a sewing machine, comprising continuously forming stitches on a cloth by repeatedly feeding needles to form stitches. 4. The stitch forming method according to claim 1, 2, or 3, wherein at least one hitch stitch is formed at each stitching point. 5. A sewing machine that forms a main stitch, a cloth feed device that feeds cloth in one direction and a direction opposite to the one direction, and the same feed after feeding the cloth feed device by (n + 1) needles in one direction. A stitch forming device for a sewing machine, comprising: a control means for continuously controlling the cloth feeding device so as to feed n needles in a direction opposite to one direction depending on the amount.