JPS61288889A - Stitch-back sewing apparatus of multihead type automatic embroidering machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is a multi-head automatic embroidery machine equipped with a plurality of sewing machine heads, and is capable of repairing missing stitches caused by thread breakage in one of the sewing machine heads. It relates to a device for.

[Conventional technology]

In a multi-head automatic embroidery machine equipped with multiple sewing machine heads (when thread breakage occurs in one of the sewing machine heads or heads during normal embroidery operation performed by driving all the sewing machine heads, the embroidery corresponding to that sewing machine head is Missing seams occur only in the fabric set in the frame.An example of a conventional method used to repair such missing seams is as follows.

After the main shaft of the sewing machine automatically stops under the control of the control means based on the detection of thread breakage by the thread breakage detection means (for embroidery machines without a bobbin thread detection device, if the bobbin thread breaks or After visually confirming that the thread has run out and stopping the main shaft of the sewing machine), replenish embroidery thread to the sewing machine head where thread breakage occurred, and stitch each embroidery hoop for the number of stitches required to start repairing. Then, among the stitch back embroidery switches provided in each sewing machine head, only the stitch back embroidery switch of the head where thread breakage has occurred is turned on. Then restart the main shaft of the sewing machine. So·
Then, under the control of the control means, the embroidery operation of the head where the thread breakage occurred is performed again at the location where the stitch is missing, while the remaining sewing machine heads are kept at rest by the jump device. As a result, missing seams can be repaired. This embroidery operation (referred to as the embroidery operation in the stitchback section) will be resumed for the number of stitches that were previously stitched back on the embroidery frame, so turn off the stitchback embroidery switch that was set earlier. put.

[Problem that the invention seeks to solve]

However, in such a repair method, the operator has to specify the sewing machine head to perform the embroidery operation in the stitchback section and cancel the designation by operating the stitchback embroidery switch, which makes the work complicated. There was a problem. In addition, if you accidentally turn on the stitchback embroidery switch on a sewing machine head with no thread breaks, not only will it be impossible to repair the missing stitches, but it will also be possible to There is a problem in that overlapping stitches are performed. Furthermore, even if you forget to turn off the stitchback embroidery switch after completing the embroidery operation in the stitchback section, the switch is provided when you later execute the embroidery operation in the stitchback section anew due to thread breakage in a different sewing machine head. Since the embroidery operation of the sewing machine head is performed again, there is a problem in that overlapping stitches are still performed on the fabric with no missing stitches.

The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide a stitchback sewing device n that can quickly and accurately repair missing stitches.

[Means for solving problems]

The stitchback sewing device according to the present invention includes a thread breakage detection means provided for each sewing machine head, a jump device for stopping the sewing operation of each sewing machine head, and a jump device for resewing stitches missing due to thread breakage. means for stitching back the embroidery frame; means for generating a first jump signal for stopping the sewing operation during the re-sewing; and means for forming a skip stitch according to the stitch data to be re-stitched; means for generating a second jump signal;
According to the thread breakage detection result for each head by the thread breakage detection means, the first jump signal is selected for the head where no thread breakage is detected, and the second jump signal is selected for the head where thread breakage is detected. means for selecting a signal;
The present invention is characterized in that the jump device for each head is controlled in accordance with the selected first or second jump signal.

Furthermore, according to the present invention, there is further provided a manual switch for individually instructing stitchback stitching for each sewing machine head, and the above-mentioned operation is performed not only based on the thread breakage detection result for each head by the thread breakage detection means but also based on the output of the manual switch. The present invention is characterized in that selection control of the first and second jump signals can be performed.

[Effect]

When a thread breakage is detected by the thread breakage detection means, each embroidery frame is stitched back by the number of stitches required to start repair. Thereafter, only the sewing machine head in which the thread breakage has been detected re-stitches the missing stitch (hereinafter referred to as "embroidery operation in the stitchback section"). That is, during this re-sewing (that is, embroidery operation in the stitchback section), the first jump signal is generated, and depending on the thread breakage detection result, the first jump signal is generated in the sewing machine head where no thread breakage has been detected. Select jump signal. Therefore, the sewing machine head in which no thread breakage is detected automatically stops its sewing operation, and only the sewing machine head in which thread breakage is detected performs the sewing operation. In this way, missing stitches can be automatically repaired without manually operating the stitchback embroidery switch for each head individually. on the other hand,
If the seams to be resewn include skipped seams,
Separately from the jump signal for nest 1 described above, a second jump signal is generated at the step of the jump stitch. The sewing machine head in which thread breakage is detected selects this second jump signal, so that the sewing operation is temporarily stopped, and as a result, a jump stitch is formed.

By the way, if only one series of jump signals is generated (if only the first jump signal is generated), there will be a jump for forming skip stitches during re-sewing, that is, during edge peeling operation in the stitchback section. Since the operation cannot be executed at all, if the location where the missing stitch occurred was a location that originally required the formation of a jump stitch (expansion of the stitch width), this cannot be done, and therefore,
A problem arises in that accurate repairs cannot be made.

However, in the present invention, thread breakage is detected by separately controlling the jump device of the sewing machine head where thread breakage is not detected and the jump device of the sewing machine head where thread breakage is detected using two systems of jump signals. The sewing machine head is designed to be able to perform a jumping motion to form jump stitches. Therefore, even if the location where a missing seam has occurred is a location that requires the formation of a skipped seam, it is possible to repair it accurately.

Further, by providing a manual switch for each head as in the second invention, selection control of two systems of jump signals can also be performed by this manual switch.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a circuit block diagram of a multi-head automatic embroidery machine employing an embodiment of the stitchback sewing device according to the present invention. This multi-head automatic embroidery machine is normally equipped with a large number of sewing machine heads, but for the sake of convenience in the drawings, it will be described as having two sewing machine heads.

Each sewing machine head is provided with needle thread breakage detectors 1a and ib for detecting needle thread breakage in the head, respectively. The output signal of the detector 1a is given to one input of the AND circuit 2a and the first input of the AND circuit 6a, and similarly, the output signal of the detector 1b is given to one input of the AND circuit 2b and the first input of the AND circuit 6b. A normal needle thread breakage detection timing signal S1 is supplied from the computer section 15, which controls input, during normal embroidery operations. A stitchback needle thread breakage detection timing signal S2 is applied from the computer section 15 to the second inputs of the AND circuits 3a and 3b, respectively, during the embroidery operation in the stitchback section.

Further, an output Q of a stitchback latch circuit 9a, which will be described later, is given to a third input of the AND circuit 3, and an output Q of a stitchback latch circuit 9b, which will be described later, is similarly given to a third input of the AND circuit 3b. .

The output of the AND circuit 2a is applied to one input of the OR circuit 4a, and the output of the AND circuit 6a is applied to the other input of the OR circuit 4a. Similarly, the output of AND circuit 2b is applied to one input of OR circuit 4b, and the output of AND circuit 6b is applied to the other input of OR circuit 4b. OR circuit 4
The output of a is the manual setting S of the needle thread breakage detection latch circuit 5a.
Similarly, the output of the OR circuit 4b is applied to the set input S of the needle thread breakage detection latch circuit 5b. An upper thread breakage reset signal S6 is applied from the computer section 15 to the reset manual power ratios of the latch circuits 5a and 5b, respectively, when the embroidery operation in the stitchback section is completed.

The output Q of the latch circuit 5a is applied to one input of the OR circuit 6, and the output Q of the latch circuit 5b is applied to the other input of the OR circuit 6. The output of the OR circuit 6 is given to the computer section 15 as a thread breakage signal S4. Further, the output Q of the latch circuit 5a is applied as an individual yarn breakage signal S5a to one input of the NAND circuit 7a, and similarly, the output Q of the latch circuit 5b is applied as an individual yarn breakage signal S5b to one input of the NAND circuit 7b.

The latch circuits 5a and 5b are each reset in the initial state. Therefore, when a needle thread breakage is detected by the needle thread breakage detector 1a or 1b, the condition of the corresponding AND circuit 2a or 2b is established at the timing of the timing signal S1 during normal embroidery operation, and the latch circuit 5a or 5b is set. Also, during the embroidery operation in the stitchback section, the corresponding latch circuit 9a or ? On the condition that b is set, the condition of the AND circuit 3a or 6b is satisfied at the timing of the timing signal S2, and the latch circuit 5a or 5b is set.

When the latch circuit 5a or 5b is turned on, the thread breakage signal S4 becomes 1" and the thread breakage individual signal 85a or S5b of the latch circuit 5a or 5b becomes 0".

Each sewing machine head is provided with stitchback embroidery switches 8a and 8b, respectively, for causing the head to perform an embroidery operation in the stitchback section when an operator discovers that thread breakage has occurred in the head. switch 8
The operation signal of switch 8b is applied to the other input of the NAND circuit 7a, and the operation signal of switch 8b is applied to the other input of the NAND circuit 7a.
It is given to the other input of b.

The output of the NAND circuit 7a is the stitchback latch circuit 9a.
Similarly, the output of the NAND circuit 7b is applied to the set power S of the stitchback latch circuit 9b. Latch circuit 9a.

When the embroidery operation in the stitchback section is completed, a stitchback end signal S6 is applied to the reset manual power R of 9b from the computer section 15, respectively.

The output Q of the latch circuit 9a is given to one input of the AND circuit 10a and the sixth input of the aforementioned AND circuit 6a,
Similarly, the output Q of the latch circuit 9b is applied to one input of the AND circuit 10b and the third input of the aforementioned AND circuit 6b. The other inputs of the AND circuits 10a and 10b are used to perform jump control of all sewing machine heads during normal embroidery operations, and to suspend control of sewing machine heads in which no needle thread breakage has occurred during embroidery operations in the stitchback section. A normal jump signal S7 is provided from the computer section 15, respectively. Further, the output Q of the latch circuit 9a is given to one input of the AND circuit 11a, and similarly the output Q of the latch circuit 9b is given to one input of the AND circuit 11b. The other input of the AND circuits 11a and 11b is supplied with a stitchback jump signal S8 from the computer section 15, which instructs jump control for forming skip stitches during the embroidery operation in the stitchback section.

The output of the AND circuit 10a is given to one input of the OR circuit 12a, and the output of the AND circuit 11a is given to one input of the OR circuit 12a.
is given to the other input of Similarly, the output of AND circuit 10b is applied to one input of OR circuit 12b, and the output of AND circuit 11b is applied to the other input of OR circuit 12b. The output of the OR circuit 12a is given to the jump solenoid 14a via an amplifier 13ai. Similarly, the output of the OR circuit 12b is given to the jump solenoid 14b via the amplifier 13b. Jump solenoid 14a
, 14b, as is well known, causes the needle bar of the sewing machine head to rest when activated by a jump signal.

The latch circuits 9a and 9b are also reset in the initial state. Therefore, thread breakage individual signals S5a, S5b
is "1" and the stitchback switches 8a, 8b
is not inserted (i.e., in a normal state in which needle thread breakage in the sewing machine head is not detected by needle thread breakage detectors 1a, 1b and not discovered by the operator), latch circuits 9a, 9b are reset. Since the state is maintained, AND circuits 11a and 1lb are enabled, and a normal jump signal S7 is applied to jump solenoids 14a and 14b, respectively. On the other hand,
When the individual thread breakage signals S5a and S5b become "O-I" or when the stitchback switch 8a or 8b is turned on (that is, when the needle thread breakage in the sewing machine head is detected by the needle thread breakage detector 1a or 1b or by the operator) If found), the corresponding latch circuit 9a or 9b is set, so that the AND circuit 10a, 10b is enabled and the jump solenoid 14a or 14b is provided with the switch jump signal S8.

In the figure, a paper tape reader 16 stores tape data consisting of X and Y data that determines the position of the embroidery frame arranged corresponding to each sewing machine head, as well as function data that determines the operation of each part of this multi-head automatic embroidery machine. It has a built-in paper tape on which data is recorded, and the tape data is read from the paper and tape. Paper tape reader 16
The tape data read in is provided to an auxiliary memory within the computer section 15. The operation panel 17 is
A tape read switch SW1 is used to execute the read operation of the paper tape reader 16, and a data set switch S is used to set various data when starting the stab operation.
W2, a stitch back switch SW6 for stitching back each embroidery frame by the required number of stitches, a start switch SW4 for driving the main shaft of the sewing machine, a stop switch SW5 for stopping the main shaft of the sewing machine, etc. It is something that Panel 17 based on switch operation
The operation signal outputted from the computer section 15 is given to the computer section 15. X-axis pulse motor 19, Y-axis pulse motor 20
, each embroidery frame 'liI: is driven in the X-axis direction and the Y-axis direction. The operation of the motors 19 and 20 is controlled by the computer s15 via the embroidery frame drive interface 18. The sewing machine main shaft motor 22 drives the sewing machine main shaft.

The operation of the motor 22 is controlled by the computer section 15 via the amplifier 21. The rotary encoder 23 is for detecting the rotation angle of the motor 22. The encoder 26 provides a signal indicating the rotation angle of the motor 22 to the computer section 15 .

In addition, each sewing machine head has a light emitting diode LE on the output line of thread breakage individual signals S5a and S5b as shown in the figure.
D is connected. The light emitting diode L E 1) is
When a needle thread breakage is detected in a corresponding sewing machine head, each light is emitted to display the needle thread breakage of the corresponding sewing machine head.

An example of the operation for repairing missing stitches in this multi-head automatic embroidery machine will be explained with reference to the flowcharts for the second cause and the following.

As shown in the second factor, when the multi-head automatic embroidery machine is turned on, the process goes through a predetermined initial routine and then goes to a sewing machine main shaft stop routine. In the sewing machine spindle stop routine, the 3rd
As shown in the figure and FIG. 4, first, in the stop initial routine, the contents of the working RAM in the computer section 15 are cleared. Next, confirm that the tape read switch SW1 on the operation panel 17 is turned on, and read the tape data (x, y data and function data).
is read out one stitch at a time by the paper tape reader 16, and the data is stored in the auxiliary memory (steps 101 to 106).
). When reading and storing all tape data is completed, it is confirmed that the data set switch SW2 of the operation panel 17 is turned on, and the count values of the stitch counter and auxiliary memory address counter A are set to zero (steps 107 to 109). . Next, it is confirmed that the stitchback switch SW3 of the operation panel 17 is not turned on and that the start switch SW4 of the panel 17 is turned on (steps 110 and 118).

The sewing machine main shaft stop subroutine is ended, and the sewing machine main shaft operation subroutine is started as shown in Fig. M2.

In the sewing machine main shaft operation subroutine, as shown in Figure 5,
After driving the sewing machine main shaft motor 22 and starting the operation of the sewing machine main shaft (step 201), the operation initialization routine is performed to initialize the working RAM and also perform the encoder clock interwoven subroutine and the encoder origin interwoven subroutine, which will be described later. Enable execution. Next, the upper thread breakage reset signal S6 is applied to the reset manual power R of the upper thread breakage latch circuits 5a and 5b to reset the latch circuits 5a and 5bi (step 202).
). Next, other operation processing of the multi-head automatic embroidery machine is performed, and it is confirmed that no needle thread breakage is detected by the needle thread breakage detector 1a or 1b, and that the stop switch S on the operation panel 17 is checked.
Execute the embroidery operation using each sewing machine head while checking that W5 is not inserted (steps 203 to 2).
07).

During the execution of the sewing machine spindle operation subroutine, the encoder 26
Each time a clock signal is applied from the machine, the sewing machine main shaft operation subroutine is interrupted and the process proceeds to an encoder clock interwoven subroutine as shown in FIGS. 6 to 8. In the encoder clock interwoven subroutine, the encoder counter is incremented by one count (step 301), and it is determined which of the various timings the current count value of the counter corresponds to (steps 302 and 316). 317.32
2) Execute processing according to the corresponding timing.

In FIG. 6, at the jump timing, the process advances from YES in step 602 to step 303, where function data corresponding to the count value of the stitch counter is read from the auxiliary memory. Next, the process proceeds to step 604, where it is determined whether the count value of counter A is greater than the count value of the stitch counter. Normally, the count value of the auxiliary memory address counter A is zero, while the count value of the stitch counter is zero or has been counted up and is positive (step 109).
, 316). Therefore, step 604 is NO, and the process proceeds to step 308. Here, it is determined whether the function data is jump data, and if YES (that is, if it is necessary to form a jump stitch), the process proceeds to step 609, and the jump signals S7 and S8 are both set as valve signals "1". Output. As a result, the signal "'1" is applied to the AND circuits 10a to 11b in FIG. 1, and since the latch circuits 9a and 9b are reset during normal operation, the conditions for the AND circuits 11a and 11b are satisfied, and the jump Jump solenoid 14a by signal S7
, 14b are energized and a jumping motion is performed for the jump stitch type acid.

Note that the jump signal S8 is not required during normal operation, but
By design, this is also output in step 309.

Returning to FIG. 6, at the output timing of the X and Y tapes of the embroidery frame, step 616 becomes YES, and step 314,
Through the process 315, the X and Y data are output and the embroidery frame is moved. Thereafter, the stitch counter is incremented by one (step 616), and the process returns.

In the eighth cause, at the upper thread breakage detection timing, step 622 becomes YES, and the process proceeds to step 323.
It is determined whether the count value of counter A is greater than the count value of the stitch counter. As mentioned above, during normal sewing operation, step 323 is No, and step 32 is
Proceed to step 6. If the function data is jump data, the process advances to step 627, and a signal "1" is output as the upper thread breakage detection timing signal S1.

When the above-described predetermined processing is completed at each timing, the sewing machine main shaft operation subroutine returns to the interrupted step and resumes the sewing machine main shaft operation subroutine.

During the execution of the sewing machine spindle movement subroutine, the encoder 26
When the origin signal is given from ζ, the sewing machine main shaft operation subroutine is interrupted each time, and the process proceeds to the encoder origin interwoven subroutine shown in the ninth cause, and the count value of the encoder counter is set to zero (step 401).
. When the settings are completed, the process returns to the interrupted step in the sewing machine main shaft operation subroutine and continues the sewing machine main shaft operation subroutine again.

During the normal embroidery operation by all the sewing machine heads, the needle thread breakage in the sewing machine head is detected by the needle thread breakage detector 1a or 1b (for example, by the detector 1a), and the needle thread breakage detection signal S4 becomes "1". Then, the sewing machine spindle stop request flag is set, the count value of the stop counter is set to, for example, 2, and the motor 22 is decelerated (steps 205, 208, 209).Next,
Sewing machine main shaft stop timing (here, count down the stop counter one count at a time, return the count value to zero, stop the motor 22, and set the sewing machine main shaft stop completion flag (steps 317 to 621)
, the process returns to the sewing machine spindle stop subroutine (step 204).

At this time, the operator replenishes thread to the sewing machine head where the needle thread breakage has been detected. At this time, the corresponding thread breakage individual signal S5a or 5sb (55a in the above-mentioned light example) becomes "0" (the corresponding I diode LED also emits light), and the corresponding stitchback latch circuit 9a or 9b ( In the above example, 9a) is set. Therefore, the corresponding jump solenoid 14a
Alternatively, 14b (14a in the above example) is placed in a state where only the stitchback jump signal S8 is applied.

In the sewing machine spindle stop routine, it is checked that the tape read switch SW1 of the operation panel 17 is not turned on and that the data set switch SW2 of the panel 17 is already turned on (steps 101, 107);
After that, after confirming that the stitch back switch SW3 of the vagina panel 17 has been turned on and causing the aforementioned auxiliary memory address counter A to hold the current count value of the stitch counter (i.e., the count value when the main shaft of the sewing machine has stopped), The stitch counter is counted down one count at a time, and the embroidery frame is stitched back one stitch at a time (steps 110 to 117). When the switch SW3 is turned off after stitching back the number of stitches required to start repair, or when the count value of the stitch counter becomes zero, the start switch 8W4 on the operation panel 17 is turned off.
After confirming that has been entered, the program returns to the sewing machine main shaft operation subroutine (steps 110, 113, and 118).

In the sewing machine main axis subroutine (and the encoder clock interwoven subroutine and the encoder origin interwoven subroutine), the above-described processing is executed again. However, this time, the count value of counter A is larger than the count value of the stitch counter due to the processing of steps 112 and 115. Therefore, at the jump timing, after reading the function data corresponding to the count value of the stitch counter from the auxiliary memory (
Step 303), it is determined that the count value of counter A is larger than the count value of the stitch counter.
04), proceed to step 305. Step 60
In step 5, it is determined whether the function data is jump data, and if ■S (7if!r, that is, if it is necessary to form a jump stitch), the process proceeds to step 306, and the signal "1" is output as the stitchback jump signal S8. # is output. After that, the process proceeds to step 607, where the signal @1'' is output as the normal jump signal S7, and the process returns.

On the other hand, if the function data is not jump data, the answer in step 305 is NO, and the process skips step 306 and proceeds to step 607, where only the signal S7 is set to 1'.

Therefore, during stitchback sewing, the normal jump signal S7 is always 1#, and the stitchback jump signal S8 is "1" only when the stitch to be resewn is a jump stitch. On the other hand, as mentioned above, among the first cause latch circuits 9a and 9b, those corresponding to the head where thread breakage was detected are set, and those corresponding to the heads where thread breakage was not detected are reset. The condition remains. Therefore, in the head where thread breakage has been detected, the AND circuit 10a or 10b is enabled and the jump signal S8 is selected, thereby performing a jump operation for forming a jump stitch. On the other hand, in the head in which thread breakage is not detected, the jump signal S7 is selected by enabling the AND circuit 11a or 11b, so that the head is always jumped during the stitchback sewing operation, and the sewing Operation is automatically paused.

Also, when stitching back stitches, for the reason mentioned above, 8
Step 326 in Figure 1!8 is YES, and Step 3
By the process of 24.325, the stitchback upper thread breakage detection timing signal S is generated at the predetermined upper thread breakage timing.
2 is output.

In this way, the embroidery operation (embroidery operation in the stitchback section) is performed only by the sewing machine head where the needle thread breakage is detected at the location where there is a missing stitch due to the needle thread breakage. Repair.

During this embroidery operation, if the needle thread breakage detector 1a or 1b (1a in the above example) detects needle thread breakage again in the sewing machine head performing the embroidery operation, the main shaft of the sewing machine will go through the process described above again. Return to the stop routine (that is, stop the embroidery operation in the stitchback section (steps 205, 208, 209, 317 to 521)
, 204). On the other hand, if a new needle thread breakage is detected by the needle thread breakage detector 1a or 1b (1b in the above example) in a sewing machine head that is not performing an embroidery operation,
Corresponding AND circuit 3a or 3b (3b in the above example)
Since the latch circuit 9a or 9b (9b in the above example) that provides a signal to the needle thread breakage detection signal S4 does not become "1" because the latch circuit 9a or 9b (9b in the above example) remains reset, stitching is performed regardless of the detection of needle thread breakage. Continue the embroidery operation in the back section.

When this embroidery operation is performed for the number of stitches that were previously stitched back for one embroidery frame (that is, when the repair is completed)
The count value of the stitch counter is incremented for each stitch by the process of step 616, and as a result, it reaches the count value of the auxiliary memory address counter again. In that case, step 604 in FIG. 6 becomes No, the process goes from step 608 to step 612, and the signal "1#" is output as the stitchback end signal S6. This resets the stitchback latch circuits 9a and 9b to the initial state. Then, jump control for normal embroidery operation is performed again for each sewing machine head.

In this way, after the repair is completed, normal embroidery operation by all sewing machine heads is resumed.

The above description shows the flow of the repair operation when the upper thread breakage in the sewing machine head is detected by the upper thread breakage detector 1a or 1b. Even if only the operator discovers the upper thread breakage, it is possible to have the worker perform the repair operation in the same way.

However, in that case, use the stop switch 8W on the operation panel 17.
5 is entered by the operator himself, the sewing machine main shaft operation routine returns to the sewing machine main shaft stop routine (
Step 206) and the point at which the corresponding stitchback latch circuit 9a or 9b is set by turning on the stitchback switch 8a or 8b of the sewing machine head where the needle thread breakage is detected by the operator are detected by the detector 1a or 1b.
This is different from when upper thread breakage is detected.

In this manner, in this multi-head automatic embroidery machine, missing stitches caused by needle thread breakage can normally be repaired without the operator operating the stitch back switches 8a, 8b of the sewing machine head at all.

〔Effect of the invention〕

As described above, according to the stitchback sewing device according to the present invention, missing stitches caused by thread breakage can be repaired without the operator operating the stitchback embroidery switch. Therefore, the operability of the multi-head automatic embroidery machine is improved, and such missing stitches can be quickly and easily repaired. Further, there is no risk of overlapping stitches or the like caused by erroneous operation of the stitchback embroidery switch, and such missing stitches can be accurately repaired. Furthermore, since jump signals are generated in two series during stitchback stitching, it is possible to reliably correct skipped stitches.

Brief Explanation of Four Sides Fig. 1 is a circuit block diagram showing an embodiment of a multi-head automatic embroidery machine employing the stitchback sewing device according to the present invention, and Figs. 2 is a flowchart schematically showing a program executed by the computer section of the embroidery machine, FIG. 2 is a main flowchart, and FIGS. 3 and 4 are examples of a sewing machine spindle stop routine part in the main flowchart of FIG. 2. Flowchart, FIG. 5 is a flowchart showing an example of the sewing machine spindle operation routine part in the main flowchart of FIG. Flowchart showing an example of a subroutine. FIG. 9 is a flowchart showing an example of an encoder origin interwoven subroutine that is similarly executed in the routine of FIG.

la, 1b -- Upper thread breakage detector, 2a, 2b, 3a,
3b, 10a, 10b, 11a, 11b --- 7-nd circuit, 4a, 4b, 6, 12a, 12b --- OR circuit,
5a, 5b... Upper thread breakage detection latch circuit, 7a, 7b
... Nando circuit, 8a, 8b... Stitchback embroidery switch, 9a, 9b... Stitchback latch circuit, 13a, 13b... - Amplifier, 14a, 14b...
・Jump solenoid, 15... Computer section, 1
6...Paper tape reader, 17...Operation panel, 18
...Embroidery frame drive interface, 19...X-axis pulse motor, 20...Y-axis pulse motor, 21...Amplifier, 22...Pecin spindle motor, 23...Rotary encoder.

Claims (1)

[Scope of Claims] 1. Thread breakage detection means provided for each sewing machine head, a jump device for stopping the sewing operation of each sewing machine head, and for resewing stitches missing due to thread breakage, means for stitching back the embroidery frame; means for generating a first jump signal for stopping the sewing operation during the re-sewing; and a second jump signal for forming a skip stitch according to the stitch data to be re-stitched. means for generating a jump signal, and the first jump signal is selected for a head in which no thread breakage is detected, according to the thread breakage detection result for each head by the thread breakage detection means, and the first jump signal is selected for the head in which thread breakage is not detected. The head that has been selected includes means for selecting the second jump signal, and the jump device of each head is controlled in accordance with the selected first or second jump signal. Stitchback sewing device for multi-head automatic embroidery machine. 2. A thread breakage detection means provided for each sewing machine head, a jump device for pausing the sewing operation of each sewing machine head, and a device for stitching back the embroidery frame in order to re-stitch missing stitches due to thread breakage. means for generating a first jump signal for stopping the sewing operation during the re-sewing, and generating a second jump signal for forming a jump stitch in accordance with the stitch data to be re-stitched. a manual switch for individually instructing stitchback stitching for each sewing machine head; and a thread breakage is detected according to the thread breakage detection result for each head by the thread breakage detection means and the output of the switch. The first jump signal is selected for a head that is not running and stitchback stitching is not instructed by the switch, and the second jump signal is selected for a head that has detected thread breakage or for which stitchback stitching is instructed by the switch. Stitchback stitching for a multi-head automatic embroidery machine, characterized in that the device comprises means for selecting a signal, and the jump device for each head is controlled according to the selected first or second jump signal. Device.