JP3332242B2 - Sewing machine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a sewing machine in response to a trouble of a needle thread.

[0002]

2. Description of the Related Art As shown in FIG. 11, an upper thread 41 of a sewing machine is supplied to a shuttle 46 through a needle hole 45 of a cloth 43 and a needle plate 44 as the needle 42 moves up and down. A stitch 48 is formed. However, the upper thread 41 is
9 (hereinafter referred to as hook stop), the upper thread 41 is not properly tightened by a balance (not shown),
An excessive amount of the upper thread 41 is sent out to the stitch 48, and an abnormal loop 50 of the upper thread 41 remains between the cloth 43 and the hook stopper 49.

When the stitch length is long and the cloth feed is large, the abnormal loop 50 comes out of the needle hole 45 of the needle plate 44 and remains on the back side of the cloth 43. This has been a particular problem in embroidery where both sides are visible, such as embroidery on a towel. Also,
When the stitch length is short and the cloth feed is small (for example, when the embroidery sewing machine has a fine embroidery pattern), the abnormal loop 50 due to the hook stop is repeated many times to form a dumpling (hereinafter referred to as a tangled thread 51). ), There is a problem that the entanglement thread 51 is clogged in the needle hole 45 of the needle plate 44, so that cloth feeding and sewing become impossible.

As shown in FIG. 12, when the needle 42 is raised, a loop 52 of the upper thread 41 is formed. Originally, the rear half 52b of the loop 52 from the needle 42 to the stitch 48 is connected to the hook point 53 of the shuttle. Is hooked, but the upper thread 41
When the front half 52a of the loop 52 from the yarn supply side to the needle 42 wraps around to the rear side of the needle 42 due to the bias of the twisting of the loop 52, and the tip 53 hooks the front half 52a (hereinafter, the front It is called hanging.) In this case, there is a problem that an excessive amount of the upper thread 41 is sent out at an abnormal timing, and an abnormal loop different from that in FIG. 11 occurs.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a sewing machine control device capable of preventing a sewing defect associated with an abnormal movement of a needle thread. To provide.

[0006]

According to a first aspect of the present invention, there is provided a sewing machine control apparatus for detecting a moving amount of an upper thread between an upper thread supply source and a needle. Means, setting means for setting an upper limit allowable value of the needle thread moving amount based on the sewing data, and control means for outputting a stop signal of the sewing machine spindle when the detected value of the upper thread moving amount exceeds the upper limit allowable value. It is comprised so that it may have.

Here, as the "detecting means", there can be exemplified a rotary encoder or the like for detecting a rotation angle of a rotary thread guide for guiding an upper thread. The "setting means" includes a data storage circuit for storing sewing data, and an upper limit allowable based on an appropriate upper thread moving amount calculated from stitch length, cloth thickness, thread type, sewing conditions, and the like in the sewing data. A combination with a setting circuit in which a conversion table for converting and setting a value is stored can be exemplified. As the "control means", a central processing unit (CPU) can be exemplified.

[0008] Further, as an embodiment of the present invention, the following aspect is provided.
(1) and (2) can be exemplified. (1) A mode in which the operation of the sewing machine is permitted until one abnormal loop due to the hook stop of the upper thread occurs, and the operation of the sewing machine is stopped when the next abnormal loop repeatedly occurs. In this aspect, even if an abnormal loop occurs, if the abnormal loop ends and the needle comes out of the needle hole of the needle plate, at least cloth feeding and sewing can be continued. When the thread is repeatedly entangled and becomes entangled, cloth feeding and sewing become impossible, and this is intended to be prevented. However, in the case of embroidery in which both sides are visible, the appearance is somewhat reduced due to one abnormal loop remaining on the back side of the cloth.

In this case, the detecting means accumulates and detects the needle thread movement amounts for a plurality of stitches. Further, the setting means sets a value obtained by adding one abnormal loop length as an allowable amount to an appropriate upper thread moving amount for a plurality of stitches obtained by calculation from a stitch length or the like in the sewing data, as an upper limit of the upper thread moving amount. Set as an acceptable value. Since this abnormal loop length is about twice the interval between the cloth and the hook, for example, the interval between the cloth and the hook is 8
If it is mm, the tolerance is generally set to 16 mm. Further, the control means compares the detected value of the needle thread movement amount for a plurality of stitches with the upper limit allowable value.

(2) The conditions are stricter than in the embodiment of (1),
Stops the sewing machine main spindle when one of the abnormal loops due to the hook stop of the upper thread, one abnormal loop due to the front hook, or excessive upper thread movement due to other causes occurs, and one abnormal loop is also overlooked. No aspect. This embodiment is intended not only to prevent the cloth feeding and sewing from being disabled by the entangled thread, but also to prevent the appearance from being deteriorated particularly in embroidery in which both sides are visible by not overlooking one abnormal loop. is there.

In this case, the detecting means detects the needle thread movement amount for one stitch. In addition, the setting means sets an appropriate upper thread moving amount for one stitch calculated from a stitch length or the like in the sewing data as an allowable amount, for example, 20 to 30% or 1 to 1 of the appropriate upper thread moving amount. The value obtained by adding 15 mm is set as the upper limit allowable value of the upper thread moving amount. Also,
The control means compares the detected value of the needle thread movement amount for one stitch with the upper limit allowable value.

According to a second aspect of the present invention, there is provided a sewing machine control device, comprising: detecting means for detecting an upper thread movement amount between an upper thread supply source and a needle; Setting means for setting an upper limit allowable value; braking means for applying a braking force to the upper thread between the upper thread supply source and the balance; and braking means when the detected value of the upper thread movement amount exceeds the upper limit allowable value. And control means for outputting a drive signal of

Here, the "detecting means" and the "setting means" are the same as those in the control device of the sewing machine according to the first aspect. Examples of the "braking means" include those that impart a magnetic resistance or a frictional resistance to the rotating yarn guide through which the upper thread is guided. The "control means" controls the braking means so as to always generate a constant braking force, or the braking means controls the braking means in accordance with the difference between the detected value of the needle thread movement amount and the upper limit allowable value. An example in which control is performed to generate motive power can be given. Also, as an embodiment of the present invention, the above aspects (1) and (2) in the sewing machine control device according to claim 1
However, instead of stopping the operation of the sewing machine, a braking force is applied to the upper thread.

According to a third aspect of the present invention, there is provided a sewing machine control device for detecting a needle thread movement timing between an upper thread supply source and a needle, and detecting a rotation angle of a main shaft of the sewing machine. And a control means for outputting a stop signal of the sewing machine spindle when the detected upper thread movement timing with respect to the rotation angle of the sewing machine spindle is abnormal.

Here, the "detection means for the upper thread movement timing" can be exemplified by a rotary encoder or the like for detecting the rotation angle of the rotary thread guide for guiding the upper thread. As "means for detecting the rotation angle of the sewing machine spindle", there are a rotary encoder mounted on the sewing machine spindle and directly detecting the rotation angle of the sewing machine spindle, and a needle bar, a balance, and the like, indirectly detecting the rotation angle of the sewing machine spindle. An example is a rotary encoder. Also, as an embodiment of the present invention, claim 1
Examples (1) and (2) of the controller of the sewing machine described above can be exemplified.

[0016]

According to the first aspect of the present invention, when the detected value of the needle thread movement amount detected by the detecting means exceeds the upper limit allowable value set by the setting means, the control means judges this. To stop the sewing machine spindle. Here, for example, the aforementioned embodiment
According to (1), it is possible to at least prevent the cloth from being fed and sewn by the entanglement thread. According to the embodiment (2), it is possible not only to prevent the cloth from being sewn and sewn by the entangled thread, but also to prevent the appearance from being deteriorated particularly in embroidery in which both sides are visible.

According to the second aspect of the present invention, when the detected value of the upper thread movement amount detected by the detecting means exceeds the upper limit allowable value set by the setting means, the control means sets the upper limit. And the braking means applies a braking force to the upper thread. Here, for example, according to the embodiment (1) (provided that a braking force is applied to the upper thread instead of stopping the operation of the sewing machine), after one abnormal loop due to the hook lock of the upper thread occurs, Since a braking force is applied to the upper thread when an abnormal loop due to the next hook stop repeatedly occurs, the hook stop is less likely to occur, and it is possible to prevent at least the cloth feeding and sewing by the entangled thread from being disabled. Further, the embodiment (2)
(Similarly, a braking force is applied to the upper thread.) According to the above, a braking force is applied to the upper thread when one abnormal loop due to the hook stop of the upper thread or excessive upper thread movement due to other causes occurs. Therefore, these phenomena in the next stitch are unlikely to occur, and an action close to the automatic thread tension can be obtained. In any of the embodiments, the sewing machine does not have to be stopped every time, thereby increasing the sewing efficiency.

According to the third aspect of the present invention, when the needle thread movement timing with respect to the detected rotation angle of the sewing machine spindle is abnormal, the control means judges this and stops the sewing machine spindle. Therefore, the present invention has the same effect as the first aspect of the present invention except for the control basis.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in an embroidery sewing machine will be described below with reference to the drawings. FIGS. 1 to 8 show a first embodiment of the present invention. In FIGS. 1 and 2, reference numeral 1 denotes a head of an embroidery sewing machine. And is attached. Needle hole 7 in needle plate 6
A shuttle 8 is disposed below the inner shuttle, and an inner shuttle is held by a shuttle stopper 9. The needle bar 3 is moved up and down with the rotation of the sewing machine main shaft (not shown), and the upper thread 10 inserted through the needle 4 and the lower thread supplied from the shuttle 8
Is formed with a stitch 35. In addition,
The distance between the cloth 11 and the hook stopper 9 in this embodiment is about 8 mm.
It is.

On the front surface of the head 1, a plurality of thread guide pieces 12, 13, and 14 for guiding the upper thread 10 supplied from an upper thread supply source (not shown) such as an upper thread bobbin to the needle 4 project. The balance 16 is provided so as to be able to move up and down with the rotation of the main shaft of the sewing machine. On the front surface above the head 1, a rotating yarn guide 1 on which the upper thread 10 is wound once or several times is provided.
7, a thread tensioner 18 for adjusting the tension of the upper thread 10, and a thread take-up spring 15 are arranged in a line.

As shown in FIG. 3, the rotating yarn guide 17 is
An optical rotary encoder 21 is provided on the inner end side of the shaft 19 as a detecting means. This rotary encoder 21
Is a rotary disk 20 having a multiplicity of slits 20a fixed to the shaft 19 so as to rotate integrally with the rotary yarn guide 17, a light emitting element 21a and a light receiving element 21b disposed at positions sandwiching the rotary disk 20. And outputs a pulse corresponding to the number of the slits 20 a in accordance with the rotation of the rotary thread guide 17, and detects the movement amount of the upper thread 10 between the upper thread supply source and the needle 4. .

FIG. 4 is a block diagram showing a control circuit of the embroidery sewing machine. Reference numeral 23 denotes a selection circuit for selecting the rotary encoder 21 corresponding to the driven needle bar 3 when a large number of needle bars 3 are being sewn. Is the selected rotary encoder 2
A counter circuit 25 for accumulating pulse signals from 1 is a timing signal generating circuit for generating a timing signal for each stitch or a plurality of stitches based on the rotation angle of the main shaft of the sewing machine. 26 is a CPU as a control means for controlling the entire embroidery sewing machine, 27 is a data storage circuit for storing embroidery data, 28 is a stitch length, a cloth thickness in the embroidery data,
This is a setting circuit in which a conversion table for setting an upper limit allowable value based on an appropriate upper thread moving amount obtained by calculation from a thread type, sewing conditions and the like is stored. 29 is a motor drive circuit, and 30 is a spindle drive motor.

In the embroidery sewing machine configured as described above, when the upper thread 10 is sent out, the rotary disk 20 is rotated integrally with the rotary thread guide 17, and corresponds to the moving amount of the upper thread 10 from the rotary encoder 21. Is output, and the detection signal is accumulated in the counter circuit 24. When the timing signal generation circuit 25 generates a timing signal for one stitch or a plurality of stitches, the CPU 26 responds to the timing signal.
Reads the detected value of the upper thread movement amount in the counter circuit 24, calculates the upper limit allowable value based on the data in the data storage circuit 27 and the setting circuit 28, and detects the detected upper thread movement amount and the upper limit allowable value. Compare with If the detected value of the upper thread movement amount exceeds the upper limit allowable value, a trouble of the upper thread 10 is determined, a stop signal for the sewing machine spindle is output to the motor drive circuit 29, and the sewing machine spindle is immediately stopped.

Here, an example of a mode of programming of the control circuit will be described with reference to FIGS. FIG. 8 shows the movement curve of the balance 16, the movement curve of the needle 4, and the cloth 11.
The drive timing of the drive frame (not shown) and the thread take-up spring 1
FIG. 6 is a correspondence diagram illustrating a rotation timing of a fifth thread and a movement timing of the upper thread. In particular, the rotation timing of the thread take-up spring 15 and the movement timing of the upper thread 10 are shown in three cases: when the upper thread is normally moved, when the hook is hooked, and when it is hooked forward.

(1) As shown in FIG. 5, the operation of the embroidery sewing machine is permitted until the upper thread 10 is hooked on the hook stopper 9 and one abnormal loop 36 occurs, and the next abnormal loop repeatedly occurs. To stop the main spindle of the sewing machine. At the time of the hook stop, as shown in FIG. 8, the rotation timing of the thread take-up spring 15 and the timing of the movement of the upper thread 10 are earlier than normal. In this embodiment, the length of one abnormal loop 36 (the cloth 11 and the hook 9 in the present embodiment) is added to the appropriate upper thread moving amount for a plurality of stitches calculated from the stitch length and the like in the embroidery data. The value obtained by adding 16 mm, which is approximately twice the interval of the upper thread, is set as the upper limit allowable value of the upper thread movement amount.

(2) As shown in FIG. 6, when flat embroidery is performed on a blouse, T-shirt, or the like, one abnormal loop due to hook stop, one abnormal loop due to front hook, or excessive upper thread due to other causes. A mode in which the sewing machine main shaft is stopped when any of the movements occurs, and one abnormal loop is not overlooked. At the time of forward running, as shown in FIG. 8, both the rotation timing of the thread take-up spring 15 and the timing of the movement of the upper thread 10 completely deviate from the normal state. In this aspect, a value obtained by adding, for example, 25% of the appropriate upper thread movement amount as an allowable amount to an appropriate upper thread movement amount for one stitch calculated from the stitch length or the like in the embroidery data,
Set as the upper limit allowable value of the needle thread movement amount.

More specifically, as shown in FIG.
Assuming that the stitch length of No. 5 is L0, it is preferable that the loop length L1 of the upper thread 10 is about L0 / 4 and the lower thread length L2 of the lower thread 37 is about L0 / 2 on the back of the embroidery of the cloth 11. Therefore, assuming that the cloth thickness of the cloth 11 is t, the appropriate upper thread moving amount for one stitch is 3L0 / 2 + 2t. For example, cloth thickness t
Is 0.5 mm, when stitch length L0 is 1 mm, 1
The appropriate upper thread movement amount for the stitch is 2.5 mm, the allowable amount is 25%, 0.625 mm, and the upper limit allowable value is 3.125 mm. In this example, the occurrence of the small loop 38 as shown in FIG. 6 is permitted, but the occurrence of an abnormal loop exceeding this is not permitted.

(3) As shown in FIG. 7, when embroidery is performed on both sides of a towel or the like, one abnormal loop is not overlooked as in the above-mentioned embodiment (2). In this embodiment, 1 is obtained by calculation from the stitch length and the like in the embroidery data.
A value obtained by adding, for example, 1 mm as an allowable amount to an appropriate upper thread moving amount for the stitch is set as an upper limit allowable value of the upper thread moving amount.

More specifically, as shown in FIG. 7, if the stitch length of the stitch 35 is L0 and the thickness of the cloth 11 is t,
An appropriate upper thread movement amount for one stitch is L0 + 2t.
For example, when the cloth thickness t is 1 mm, the stitch length L0 is 3 m.
When the length is m, the appropriate upper thread movement amount for one stitch is 5 mm, and the upper limit allowable value is 6 mm including the allowable amount of 1 mm.
Also in this example, the occurrence of the small loop 39 as shown in FIG. 7 is allowed, but the occurrence of an abnormal loop exceeding this is not allowed.

Next, a second embodiment of the present invention will be described with reference to FIGS.
Description will be made based on 0. In the control device of the embroidery sewing machine according to the second embodiment, as shown in FIG. 9, as a braking means for applying a braking force to the upper thread 10 via the rotating thread guide 17 by applying a magnetic resistance to the rotating disc 20. Of the magnetic brake 32 is provided. In FIG. 10, reference numeral 33 denotes a brake drive circuit for driving the magnetic brake 32;
U26 controls the braking force of the magnetic brake 32 based on the deviation between the detected value of the needle thread movement amount and the upper limit allowable value. In FIGS. 9 and 10, the same reference numerals as those in the first embodiment denote the same members.

Therefore, when the upper thread 10 is sent out, a detection signal of the amount of movement of the upper thread 10 is accumulated in the counter circuit 24 as in the first embodiment. In response to the timing signal of the timing signal generation circuit 25, the CPU 26 reads the detected value of the needle thread movement amount of the counter circuit 24 and calculates the upper limit allowable value based on the data of the data storage circuit 27 and the setting circuit 28. Then, the detected value of the needle thread movement amount is compared with the upper limit allowable value. If the detected value of the needle thread movement amount exceeds the upper limit allowable value, the magnetic brake is determined based on the difference between the two values.
The braking force 32 is controlled, and a tension corresponding to the amount of movement acts on the upper thread 10.

Here, for example, the mode (1) of the first embodiment
If a mode corresponding to the above is adopted, after one abnormal loop due to the hook stop of the upper thread occurs, the braking force is applied to the upper thread 10 when the abnormal loop due to the next hook stop occurs repeatedly, The hook stop is less likely to occur, and it is possible to prevent at least the inability of the cloth feed and sewing by the entanglement thread. If a mode corresponding to the mode (2) is adopted, a braking force is applied to the upper thread 10 when one abnormal loop due to the hook lock of the upper thread or excessive upper thread movement due to other causes occurs. Therefore, these phenomena in the next stitch are unlikely to occur, and an action close to automatic thread tension can be obtained. In any of the embodiments, the sewing machine does not have to be stopped every time, so that the sewing efficiency is improved.

In the second embodiment, the function of stopping the main spindle of the sewing machine of the first embodiment is added, and when the moving amount of the upper thread 10 exceeds an abnormal value larger than the upper limit allowable value, the main spindle of the sewing machine is immediately moved. It may be configured to stop.

Next, a third embodiment of the present invention will be described with reference to FIGS. 1 to 8 of the first embodiment. The control device of the embroidery sewing machine according to the third embodiment is intended to control using the shift of the upper thread movement timing when the hook is hooked or when the hook is hooked as shown in FIG. In the present embodiment, the setting circuit 28 sets an appropriate needle thread movement timing with respect to the rotation angle of the sewing machine main spindle, and the CPU 26 reads the detected value of the needle thread movement timing from the counter circuit 24. At the same time, based on the data of the data storage circuit 27 and the setting circuit 28, when the detected value of the needle thread movement timing with respect to the rotation angle of the sewing machine spindle becomes abnormal, a stop signal of the sewing machine spindle is output. . Therefore, only the basis of control is different from that of the first embodiment, and the other portions have the same operation and effect.

The present invention is not limited to the above-described embodiment. For example, the shape and configuration of each part may be changed without departing from the spirit of the present invention, for example, by appropriately changing the installation locations of the detecting means and the braking means. Can be changed as appropriate and embodied.

[0036]

As described in detail above, according to the sewing machine control device of the present invention, it is possible to prevent sewing failures related to abnormal movement of the upper thread, and to prevent at least the cloth feed and sewing failure due to the entangled thread. It has an excellent effect that it can be done.

[Brief description of the drawings]

FIG. 1 is a front view of an embroidery sewing machine showing a first embodiment of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a cross-sectional view of the rotary thread guide of FIG. 1 showing an example of a detecting unit.

FIG. 4 is a block diagram illustrating a control circuit of the embroidery sewing machine of FIG. 1;

FIG. 5 is a partially enlarged view of FIG. 2 when an abnormal loop occurs.

FIG. 6 is an enlarged sectional view of flat embroidery by the embroidery sewing machine of FIG. 1;

FIG. 7 is an enlarged sectional view of double-sided embroidery by the embroidery sewing machine of FIG. 1;

FIG. 8 shows a movement curve of a balance in the embroidery sewing machine of FIG.
FIG. 6 is a correspondence diagram of a movement curve of a needle, a drive timing of a cloth drive frame, a rotation timing of a thread take-up spring, and a movement timing of an upper thread.

FIG. 9 is a sectional view showing a braking means in the embroidery sewing machine according to the second embodiment of the present invention.

FIG. 10 is a block diagram showing a control circuit of the embroidery sewing machine according to the second embodiment.

FIG. 11 is a partial cross-sectional view of a conventional example when entanglement occurs.

FIG. 12 is a partial cross-sectional view of a conventional example when a front hanging occurs.

[Explanation of symbols]

 4 Needle 10 Needle thread 16 Balance 17 Rotary thread guide 21 Rotary encoder 26 CPU 27 Data storage circuit 28 Setting circuit 32 Magnetic brake

Claims (3)

(57) [Claims] 1. A detecting means for accumulating and detecting a plurality of stitches for a plurality of stitches between a needle thread supply source and a needle, and an appropriate amount for a plurality of stitches obtained by calculation from a stitch length or the like in sewing data. A setting means for setting a value obtained by adding one abnormal loop length as a permissible amount to the upper thread moving amount as an upper limit allowable value of the upper thread moving amount, and one abnormal loop due to the hook stop of the upper thread occurs. Control means for permitting the operation of the sewing machine up to and outputting a stop signal of the sewing machine main spindle when the next abnormal loop repeatedly occurs, that is, when the detected value of the upper thread movement amount for a plurality of stitches exceeds the upper limit allowable value. A control device for a sewing machine, comprising: 2. A detecting means for accumulating and detecting a plurality of stitches of a needle thread between a needle thread supply source and a needle, and an appropriate number of stitches calculated by a stitch length or the like in sewing data. Setting means for setting a value obtained by adding one abnormal loop length as an allowable amount to the upper thread movement amount as an upper limit allowable value of the upper thread movement amount, and controlling the upper thread between the upper thread supply source and the balance. The operation of the sewing machine is permitted until one abnormal loop occurs due to the braking means for applying power and the hook stop of the upper thread, and when the next abnormal loop occurs repeatedly, that is, the upper thread movement amount for a plurality of stitches And a control means for outputting a drive signal of the braking means when the detected value exceeds the upper limit allowable value. 3. A detecting means for detecting a timing of moving the upper thread between the upper thread supply source and the needle, a detecting means for detecting a rotation angle of the main shaft of the sewing machine, and one abnormal loop caused by the hook lock of the upper thread. The sewing machine is allowed to operate until it occurs, and the next abnormal loop repeatedly occurs, that is, when the needle thread movement timing with respect to the detected rotation angle of the main shaft of the sewing machine becomes abnormal enough to repeatedly generate the next abnormal loop. And a control means for outputting a stop signal of the sewing machine spindle.