JP2746553B2 - Method of producing a seam having a seam break in a sewing product and a sewing machine for performing the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a seam having a seam break in a sewing product and a sewing machine for performing the method.

[0002]

2. Description of the Related Art Catalog "Puff 3823 NO.2"
96-12-13629 German, English, French, West "04/8
No. 6 discloses a sewing machine equipped with a sewing machine having the configuration according to the premise of claim 4 of the present application, that is, a sewing machine including a sewing machine having a transport device, a thread cutting device, a stitch interrupting device, and a cutting device. This sewing facility is provided for sewing and cutting a sewn product. In order to machine the armhole area in the left front part of the outerwear, it is stated that the sewer first turns on the stitch interrupter and turns on the cutting device to start the work. That is, cutting is performed without sewing.
Following processing of the sewn article, the stitch interrupter is turned off. As a result, when the work further proceeds, sewing and cutting of the sewn product are performed. In order to process the right front part of the outerwear, it is necessary to reverse the working order.

[0003] Regarding the working mode of the stitch interruption device,
It is known to interrupt stitching by blowing off the upper thread held by the looper. In the case of this type of device, when the stitch interruption device is turned on, the upper thread is tightened under the cloth presser and pulled out as the sewing material is transported. Such excess yarn requires special care in further processing the outerwear. To solve this problem, excess yarn is often cut by hand in a special operation.

It is widely known to use a sewing machine with a thread cutting device when forming a seam with a seam break in a sewing product. In this case, after the formation of the seam,
The thread cutting process is performed, and the cloth retainer and the sewing product are lifted. Next, the sewing product is advanced by hand, the cloth holder is lowered again, and then the sewing process is continued. Such a procedure is only effective if the seam breaks extend over a relatively long distance and if the manipulation and repositioning of the sewing material under the presser foot does not result in a loss of time or a loss of quality. . In this connection, German Patent No. 38184
No. 57, it is known to move a sewn article using a sewn article clamp after one stitch is formed. In this case, the sewing machine itself is stopped. In order to make this possible, a clutch is provided between the sewing machine and the sewing clamp so that the sewing machine and the sewing clamp can be driven and separated from each other. Furthermore, from DE 236 1989 and DE-A-3 026 732, a stitching device or an error stitching device is provided on the sewing machine to interrupt normal stitch formation once a certain transport distance is exceeded.
That is, it is known that the entanglement of the upper thread and the lower thread is interrupted. In this case, a long stitch can be formed considerably as compared with a normal stitch. While forming such stitches (resulting in stitch breaks)
Also, the yarn is pulled out.

According to a method for interrupting stitches in a sewing machine known from US Pat. No. 2,830,955,
A device that pulls back the upper thread in the stitch forming cycle is used, and thus the upper thread loop held by the looper is pulled back. According to this publication, it is possible to form a seam with a seam break, but on both sides of the sewn material there is a seam thread over a distance that has not been sewn.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to improve a method and a sewing machine of this kind in the following way, that is to say that a seam with a seam break can be reliably formed. That is.

[0007]

According to the present invention, there is provided a method for continuously tightening and fixing a thread supplied to a needle while a seam break occurs. It is a feature.

In the sewing machine for carrying out the above method, the device for preventing stitch formation has a thread clamp for an upper thread disposed between a balance and a needle, and the thread clamp is provided with a stitch formation device. Operable to tighten the upper thread in order to prevent the upper thread.

A feature of the invention is that the supply of thread extending to the needle is completely interrupted during the formation of the seam break. This ensures that undesired withdrawal of the thread while forming the seam break is prevented. This is also the case when the needle thread is caught on the part of the looper where the needle thread is rotating or the looper itself due to an unforeseen situation, and the needle thread is moving upward, causing the needle thread to be cut. Achieved. While forming the seam break, the thread end hanging from the needle hole of the needle is gripped by the looper tip at each stitch and pulled under the sewing product. However, each time the needle is raised, it is withdrawn again from the sewing product.

[0010] The sewing machine for carrying out the method according to the invention requires that the thread cutting device, which is arranged below the sewing material mounting plate, be provided with a clamp for clamping the cut lower thread. As a result, the thread clamp used is only used to prevent thread from being fed to the needle. By configuring the thread clamp according to the configuration of claim 5, the friction force acting on the upper thread can be changed. This makes it possible to compensate for the influence caused by the difference in the thickness of the yarn. Further, it is possible to compensate for various values of frictional force due to the difference in the type of thread and the material of the sewing product.

According to another embodiment of the present invention, the number of stitches can be counted. as a result,
The seam break to be formed can be pre-adjusted with respect to its distance or length. This relieves the operator of the sewing machine from control duties, thus resulting in increased production and product quality.

A thread clamp used in accordance with claim 4 is already known from DE 36 04 299, but according to the invention, in order to carry out the method according to the invention, the first stitch of the seam is required. When forming
Used to pull the thread end of the upper thread from the surface of the sewing product on the lower surface of the sewing product. According to the above-mentioned known publication, the problem is solved by operating the thread clamp for a short time while pulling out the first upper thread loop from the tip of the looper. This means that the looper tip in the present invention acts as a yarn pulling means for dragging the yarn end of the upper yarn down. Said publication does not propose using a thread clamp as in the present invention. Rather, another method is implemented in the present invention. That is, the known thread clamp having the same configuration and the same arrangement is used to solve a completely different problem. Almost nine years have passed since the invention of the method described in the above-mentioned publication was proposed, and this type of treatment has attained the invention.

[0013]

Next, an embodiment of the present invention will be described with reference to the accompanying drawings. The sewing machine 1 is arranged on a table 2.
Further, the sewing machine 1 includes a stand 3 extending substantially vertically.
have. A case-like upper arm 4 and a case-like lower substrate 5 also extend horizontally from the stand 3. The sewing machine 1 has a normal C-shape. The upper boundary edge of the substrate 5 forms the mounting plate 5a. An upper shaft 6 is supported by the arm 4. A flywheel 7 is fixed to one end of the upper shaft 6 outside the stand 3. The driving of the upper shaft 6 is performed by a driving device 8 attached to and controlled on the lower surface of the table 2. The driving device 8 mainly includes a motor 9 having a control unit 10. Inside the control unit 10, a numerical control circuit 10a is housed in addition to a normal digital control part for driving. An externally operable two-digit decimal input key 10b is connected to the numerical control circuit 10a as an input device. FIG. 1 illustrates a state in which the digital input key 10b is input with a numerical value 24. Motor 9
The drive transmission from the flywheel 7 to the flywheel 7
This is performed using

The upper shaft 6 allows, as usual, the inside of the head,
That is, the needle bar 12 supported in the front part of the arm 4 is driven up and down. Similarly, the upper shaft 6 drives the looper 13 via a rotation drive transmission device provided in the stand 3 and the substrate 5. The rotation speed of the looper 13 corresponds to twice the rotation speed of the movement of the needle bar 12. Generally, the looper 13 is also called a thread wheel receiving portion. A position detector 14 is connected to the upper shaft 6 so as not to rotate relatively. The position detector 14 outputs a signal indicating the number of rotations and the rotation position of the upper shaft 6,
The signal is sent to the control unit 10 via the signal transmission line 15.

A thread spool 16 having a thread storage section is arranged on the arm 4. This yarn is hereinafter referred to as the upper yarn 17. The upper thread 17 is guided to the thread tension 19 via the turning portion 18, and from there to the balance 20. The upper thread 17 is guided by the thread hole 21 of the balance 20. Balance 2
From 0, the upper thread 17 is guided substantially vertically downward and reaches the needle 23 through the thread clamp 22. The needle 23 is the needle bar 12
It is fixed to. The needle 23 has a needle hole 24 for guiding the upper thread 17. When the needle 23 moves up and down, the needle hole 25
Penetrate through. The needle hole 25 is formed on the puncture plate 26 by the needle 23.
Are arranged so as to be aligned with the motion trajectory. Puncture board 2
6 is fixed to the substrate 5 so that its upper surface extends in alignment with the mounting plate 5a. The looper tip 27 of the looper 13 passes by the needle 23 or its vertical motion trajectory.

The presser foot 2 which moves up and down in parallel with the needle bar 12
8 is supported in the arm 4. The presser foot 29 of the cloth presser 28 is pressed against the sewn product 30 placed on the mounting plate 5a or the upper surface of the needle plate 26 at the settling position.

Below the needle plate 26, a thread cutting device 31 is attached. The thread cutting device 31 has components fixed to the substrate 5, and includes, for example, a cutter 31a, a tightening spring 31b, and a thread pulling cutter 31c that can rotate concentrically with the looper 13. The thread pulling cutter 31c is connected to a driving device not described in detail here. With this driving device, the yarn pulling cutter 3
1c is capable of reciprocating between a rest position shown in FIG. 5 and a capture position shown in FIG. Such a yarn cutting device is known.

A thread storage section is supported in the looper 13. This yarn is hereinafter referred to as the lower yarn 32. A cloth feed 61 is disposed below the needle plate 26. The configuration of the cloth feed 61 corresponds to a normal configuration. The cloth feed 61 is drivingly connected to the upper shaft 6 via a transmission, which will not be described in detail. Thus, the cloth feed 61 performs a rectangular bouncing motion at the cycle of the needle motion. The cloth feed 61 partially protrudes through the slit in the needle plate 26 and temporarily engages with the sewing product 30.

The thread clamp 22 comprises a casing 33 provided with a fixing plate 34. The fixing plate 34 includes a screw 35
Is fixed to the arm 4. The casing 33 is
It has a thread receiving slit 37 extending transversely to the central longitudinal axis 36 and extending in the direction of the upper thread 17, that is, substantially vertically. The thread receiving slit 37 allows the balance 20
The upper thread 17 extending from the needle 23 to the needle 23 can be pulled. The upper thread 17 is inserted into the thread guide hole 3 in the thread receiving slit 37.
8 is held. An elastic thread clamp support member 39 is arranged on one side of the thread receiving slit 37. The thread clamp support member 39 is formed in a container shape, and is in contact with a coil compression spring 40 which can be tensioned in advance. The coil compression spring 40 is supported by an adjustment screw 41. The position of the adjusting screw 41 is adjustable in the direction of the central longitudinal axis 36 of the casing 33. Such an adjusting movement changes the tension of the compression spring 40. Upper thread 1
7 abuts against the bottom surface of the thread clamp support member 39 used as the tightening surface 42, and
Is held in the rest position shown in FIG. 3 by the stopper flange 43, and can move only against the force of the compression spring 40. On the side opposite to the thread clamp support member 39, a clamp piston 44 that can be biased by air pressure is attached. The clamp piston 44 is movably accommodated in a cylindrical space 45 capable of supplying compressed air to one side. The clamp piston 44 carries in the annular groove a stopper 46 configured as a snap ring. The stopper 46 is connected to the casing 33
Protrudes while having play in the slit 60. The play is created by making the slit 60 wider relative to the stopper 46, so that the clamp piston 44 can reciprocate between the two end positions. The size of the play is selected so that when the clamp piston 44 and the thread clamp support member 39 are at their rest positions, the upper thread 17 can pass through the thread clamp 22 even if it has the largest possible thickness. Have been. The clamp piston 44 protrudes from the cylindrical space 45, with the end face of the clamp piston 44 used as a pressing surface facing the upper thread 17. A compressed air pipe 48 is opened at a portion of the cylindrical space 45 opposite to the pressing surface 47. When the clamp piston 44 is urged by compressed air, the clamp piston 44 travels from the illustrated rest position to the outer end position limited by the stopper 46, at which time the upper thread 17 is pressed against the pressing surface 47 and the thread clamp supporting member. Between the first and second fastening surfaces 42. Compressed air pipe 48
Inside, an electromagnetic valve 49 is provided. The solenoid valve 49
Is controlled by the control unit 10 via the control lead 50.

Next, the operation will be described. It is assumed that the sewing machine 1 is operating, and thus a seam 62 is formed on the sewing product 30. At that time, according to the sewing machine 1 described above, the sewing product 30
Alternatively, the holding of the sewn product 30 or 30a is performed stepwise by the cloth feed 61. In this state, the compressed air pipe 48 is in a pressureless state, so that the upper thread 17 can pass through the thread clamp 22 without any trouble. While the seam 62 is being formed, the sewing product 30 advances in the transport direction 54 toward the stationary sewing machine 1 and reaches the point A. Next, the upper thread 17 and the lower thread 32 are cut by the thread cutting device 31 according to a control command of the operator. Thereafter, the thread tension cutter 31c is in its rest position, in which case the bobbin thread 32 is tightened between the thread tension cutter 31c and the clamping spring 31b. This means that the tightening of the bobbin thread 32 is performed below the sewing product 30 or 30a. Finally, the sewing machine 1 comes to a rest state, in which the needle is at its top dead center, ie in the needle up position. Needle 2 in this state
The free end of the needle thread 17, which lies in the hole 24, is outside the sewing product 30. Nevertheless, the cloth presser foot 29 remains in the above-described settling position, that is, is placed on the sewing product 30 as it is.

Next, a control command is issued to the control unit 10. As a result, the solenoid valve 49 operates. as a result,
Compressed air is supplied to the compressed air pipe 48. For this reason, the upper thread 17 is held without interruption between the pressing surface 47 of the clamp piston 44 and the clamping surface 42 of the thread clamp supporting member 39, that is, is always clamped and held. According to another control command, the sewing product 30
Is further transported in the transport direction 54. In the meantime, the needle 23 is pierced into the sewn product 30 in the same manner as in the sewing process, in which case it is impossible to form a stitch with the upper thread 17 which is clamped and held by the thread clamp 22. Stitching refers to threads 17 and 32 forming seams 62, 63 or 64.
It is a tangled process. In order to prevent stitch formation, the looper tip 27 grips the upper thread 17 carried by the needle 23 below the needle plate 26 in the same way as in a normal sewing process, but pulls it by tightening with the thread clamp 22. It is not possible. Accordingly, the upper thread 17 is not guided around the looper 13 by the looper tip 27, and as a result, the lower thread 32 is
It remains clamped between 1c and the clamping spring 31b.

The frictional force acting on the upper thread 17 during the operation of the device for preventing stitch formation is adjusted so that the high tensile force generated by chance on the upper thread 17 does not exceed the frictional force. . This means that stitch formation is reliably prevented and any undesired withdrawal of the upper thread is prevented.

The transport of the sewn product 30 is performed until the needle 23 pierces the sewn product 30 at the point B and reaches the lowermost position. The lowermost position is where the needle 23 is the deepest
This is the position where you are entering. This is usually done simply by releasing the pedal for controlling the drive 8 in the case of a sewing machine with a positioning motor. As a result, the sewing machine 1 automatically stops at the aforementioned position (needle dropping position).

Further, by issuing a control command, the solenoid valve 49 is switched, and as a result, the compressed air pipe 48 is deenergized, so that the tightening of the thread clamp 22 on the upper thread 17 is released.

Subsequently, when the sewing machine 1 is operated again, the looper 13 can pull out a sufficient amount of the upper thread 17 to form a stitch. As a result, the seam 63 can be formed. Point A where stitch formation is not performed
The distance between B and B is defined as a seam break AB.

In another application example according to FIG. 7, the corresponding work process is described for a sewn product 30a showing an armhole in the right front part of the jacket. In this case, a normal sewing process is performed at the point C. At this time, the thread clamp 22 is in a state without pressure, and the upper thread 17 can pass through the thread clamp 22 without any trouble. In this case, the seam 64 is formed while the conveyance of the sewing product 30a is performed by the conveyance device 54. As is known with this type of sewing machine, the cutting of the edge 65 by an edge cutter (not shown) attached to the sewing machine 1 is performed simultaneously with the sewing process. After the sewing and cutting process, point D is reached, at which point the seam 64 for each control command ends with a thread cutting process, and finally the needle 23 stops again at the needle raising position. As a supplementary explanation, the band 66 may be sewn by the seam 64 used to secure the shape of the arm hole region.

After a new control command is issued, the yarn clamp 22 is energized with compressed air. As a result, again, uninterrupted thread tightening of the position 17 supplied to the needle 23 is achieved. Subsequently, the sewn product 30a is further transported in the transport direction 54, at which point stitch formation is prevented, and only the cutting process is performed until all work steps have been completed at point E. The distance between points D and E, performed without stitching, is the seam break DE.

As described above, the seam 30 is formed with seams 62 and 63 having seam breaks A and B. The seam breaks A, B can be, for example, mounting holes for multilayer sewing products. In the last-mentioned application example, the sewing machine 1 is used for performing another operation (here, cutting of an edge) when a seam is not formed.

In another embodiment of the sewing machine according to the invention, the input for the distance of the seam break AB; DE is made indirectly by presetting the number of rotations of the upper shaft 6. Assuming that the set stitch length of the sewing machine 1 is 2.5 mm, when the set number is 24, the distance of the seam interruption portion AB is 2.5 mm / stitch × 24 stitches = 60 mm. During the transport of the sewn product 30 or 30a, ie during the occurrence of the seam break AB or DE,
Stitch counting is performed. At that time, the count control circuit 10a receives the signal of the position detector 14 and counts the number of rotations of the upper shaft 6, that is, the number of stitches performed by the needle 23 without generating the seam 30 or 30a. When the count set on the digital input key 10b is completed, the count control circuit 10a stops the sewing machine 1 with the needle 23 positioned at the needle raising position.

[Brief description of the drawings]

FIG. 1 is a front view of a sewing machine having a configuration according to the present invention.

FIG. 2 is a side view of the thread clamp attached to the head of the sewing machine, as viewed in the direction of arrow II in FIG.

FIG. 3 is an enlarged cutaway view of the yarn clamp, and is indicated by an arrow I in FIG.
It is the figure seen in the II direction.

FIG. 4 is a side view of the sewing machine as viewed in the direction of arrow I in FIG. 1;

FIG. 5: The looper tip pulls the upper thread below the sewing product,
After the bobbin thread that was cut before that was tightened,
It is a figure showing a needle at the time of a needle rise.

FIG. 6 is a perspective view of a portion of a sewn article having a seam with a seam break;

FIG. 7 shows another part of the sewn product in which one stitch and the next stitch break are implemented.

[Explanation of symbols]

1 sewing machine 17 needle thread 22 thread clamp 23 needle 30, 30a sewing product 3
2 Lower thread 62, 63, 64 Stitch AB, DE Stitch break

Continuation of the front page (72) Inventor Archim Foss, Germany 32139 Spenge Herfolder Strasse 10 (56) References JP-A-5-177075 (JP, A) JP-A-61-100291 (JP, A) JP-A-5-115647 (JP, A) JP-B-37-8233 (JP, B1)

Claims (6)

(57) [Claims] 1. A seam break at a sewing product (30; 30a).
A method of producing a seam (62; 63; 64) having (AB; DE), wherein a sewing product (30; 30a) is held and transported with respect to a needle (23) of a sewing machine (1), A seam (62; 63; 64) having an upper thread (17) and a lower thread (32) is produced, wherein the upper thread (1
7) supplying the needle (23) to the needle (23); tightening the lower thread (32) below the sewing product (30; 30a) to cut the thread; and holding the sewing product (30; 30a). Transporting to produce a stitch break (AB; DE); and operating the device for preventing stitch formation without interruption during the stitch break (AB; DE). Shutting off the device for preventing stitch formation to produce the next seam (62; 63; 64), wherein the seam break (AB; DE) is produced. While
A method comprising continuously tightening and fixing the upper thread (17) supplied to the needle (23). 2. During the creation of the seam (64) and during activation of the device for preventing stitch formation,
2. The method according to claim 1, comprising the step of cutting the edge (65) of the sewing product (30a). 3. A band while creating a seam (64).
3. The method according to claim 1, further comprising the step of sewing (66). 4. A sewing machine for carrying out the method according to claim 1, comprising a mounting plate (5a) for a sewing product (30; 30a), a cloth presser (28), and a cloth feeder (28). 31), a storage part for the upper thread (17), a balance (20) for the upper thread (17), and a needle (23) for guiding the upper thread (17), 17) is supplied from the storage unit to the balance (20), and the upper thread is supplied from the balance (20).
A needle (23) capable of supplying (17), and a thread wheel receiving portion (13) for guiding the lower thread (32), wherein the upper thread (17) and the lower thread (32) are formed in order to form a stitch. Said thread loop receiving portion (13) for guiding a lower thread (32) arranged below the mounting plate (5a) for the stitches (62; 63; 64) having; It is located below and has a seam (62; 63;
64), a thread cutting device (31) for cutting the upper thread (17, 32), interrupting the stitch formation and forming a stitch break (AB; DE) And a device operable without a stitch, wherein said device for preventing stitch formation comprises a balance (20) and a needle.
(23) A thread clamp (2) for the upper thread (17) arranged between
2) a sewing machine, characterized in that the thread clamp (22) is operable to tighten the upper thread (17) to prevent stitch formation. 5. Sewing machine according to claim 4, wherein the thread clamp (22) is adjustable with respect to the frictional force acting on the upper thread (17). 6. A control unit (10) for controlling the thread clamp (22) is provided, the control unit (10) generating a numerical control circuit (10a) and a seam break (AB; DE). The sewing machine according to claim 4 or 5, further comprising an input device for presetting the number of rotations of the upper shaft (6) during the operation.