JPS63315095A - French seam inferiority detector - 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] "Industrial Application Field" This invention is a device for machine sewing the open end of a bag, and the sewing machine is capable of reliably sewing the open end of a bag, and of not cutting the bag in order to properly sew the next bag. The present invention relates to a bag sewing machine sewing defect detector that detects whether or not the bag sewing machine has been stitched properly.

``Conventional technology'' Granular products such as rice and other grains, granular fertilizers, and synthetic resin pellets are often sold in bags. The upper open end is sewn shut using a sewing machine and then sent out.

In this process, accidents occur where the sewing thread supplied to the bag breaks and the sewing machine cannot sew, or when the sewing machine finishes sewing one bag, the sewing thread is cut from this bag and used for the next one. Sewing is carried out on the bags that are sent, but if the sewing machine fails to cut the sewing thread, it will not be possible to properly stitch the bags that are sent next. When these sewing defects occur, they are detected and
It is necessary to take appropriate measures.

However, in the past, the former type of thread breakage was used to detect poor stitching, but the latter type of thread breakage was not detected based on the sewing machine thread breakage. required.

In addition, in order to detect the former thread breakage, in the past, the movable element of a limit switch was brought into contact with both the upper thread and bobbin thread supplied to the bag. It was designed to work and detect thread breakage. However, such a detector is affected by the tension of the thread, and has a problem in that the limit switch often operates even when no thread breakage has occurred, resulting in false detection.

"Means for Solving the Problem" According to the present invention, a thread fluctuation detection sensor is provided in each passage of the upper thread and bobbin thread of the sewing machine that is supplied to the bag, and each sensor detects the movement of the thread. Outputs that vary depending on whether the bag is present or not are obtained, and a judgment circuit detects poor sewing on the bag from the outputs of these sensors.

In other words, when the sewing machine is sewing normally, both the upper thread and the lower thread are fed out from the bobbin, and the thread is moving.In this state, there is slight fluctuation in the thread due to the movement, Due to slight variations in thickness, the output of the sensor will vary. However, when a thread breakage occurs, the thread is not paid out from the bobbin and the movement of the thread stops, and the output of the sensor remains at a constant value. Therefore, when the sewing machine should normally be sewing, if the sensor output does not fluctuate and remains constant, the determination circuit determines that thread breakage has occurred.

On the other hand, when the machine sewing for one bag is finished, the thread is cut. Therefore, if the thread is cut, the thread will not be fed out until the machine starts sewing the next bag, but if the thread cutting fails, the bag will be cut. The sewing thread is pulled as it moves,
The thread is fed out from the bobbin. Therefore, if the output of the sensor fluctuates when the yarn is cut and the yarn is not normally paid out, the determination circuit determines that the yarn cutting has failed.

``Example'' Figure 1 shows an example of this invention.0 A bag like a paper bag1)
is filled with granular products, and the bag 1) is transferred to belt conveyor 1.
2, they are sent one after another to the positions of the sewing machine as shown by arrow 13. An upper thread 16 and a lower thread 17 are paid out from the upper thread bobbin 14 and the lower thread bobbin 15, respectively, and are supplied to the bag 1) through the sewing machine needle 18, and sewing is performed on the upper open end of the bag II. . As a result gt1)
A seam 19 appears. When the machine sewing for one bag 1) is completed, the upper thread 16 is cut by a cutter not shown in the figure.
, the bobbin thread 17 is cut and separated from the bag 1), and when the next bag is sent, the machine stitching is performed again.

In this invention, thread fluctuation detection sensors 21 and 22 are provided in each passage of the upper thread 1) and lower thread 17.

The output of the yarn fluctuation detection sensors 21 and 22 fluctuates when the upper thread 16 and the lower thread 17 are unwound from each bobbin and are moving, and output a constant output when the thread movement is stopped. As these sensors, transmission type photosensors, capacitance type sensors, etc. can be used. Here we show an example using a transmission type photo sensor.

For example, as shown in FIG. 2, in the transmission type photosensor, a recess 32 is formed on one side of a sensor case 31, a thread guide 33 is attached to the upper and lower surfaces of the recess 32, and a thread 34 is inserted into the notch of the thread guide 33.
is passed. If the sewing machine is correctly sewing the nine bags 1) in which the light emitting element 35 and the light receiving element 36 are placed across the path of the thread 34 in the recess 32, both the upper thread 16 and the lower thread 17 are paid out from the bobbin. move while In this state, both the upper thread 16 and the lower thread 17 are swinging while vibrating slightly. Further, the upper thread 16 and the lower thread 17 are each twisted from a plurality of threads, and their thicknesses vary slightly. For these reasons, the outputs of the photosensors 21 and 22 vary while the yarn is being paid out. For example, for sewing thread with a diameter of about 1 m,
When an infrared light emitting diode with a light beam diameter of about 5 mm is used, when the thread is being paid out, the output of the photosensor 21 of the upper thread 16 fluctuates as shown in FIG. 3A, and the output of the lower thread I7
The output of the photosensor 22 fluctuates as shown in FIG. 3B. - When the bobbin thread is not paid out, the photo sensor 21
．． The outputs of 22 are both constant values.

Therefore, by monitoring fluctuations in the output of the photo sensors 21 and 22, if the output becomes constant when sewing should be performed, the upper thread 16 or bobbin thread 17 corresponding to that sensor will break midway. This can be seen when the thread stops being fed out due to an accident, or when the sewing machine has finished sewing one bag and is waiting for the next bag to be sent, that is, the sewing machine is interrupted and When the sewing thread is separated from the bag, the upper thread 16
, the bobbin thread 17 is not let out, and the outputs of the photosensors 21, 22 remain constant; Alternatively, if the output of 22 is fluctuating, it can be determined that the thread cutting has failed and the thread is being pulled and being let out due to the movement of the bag.

To make the above-mentioned judgment, it is necessary to judge whether the sewing machine is actually in operation or stopped, or more precisely, whether the sewing machine is stopped after the sewing machine has finished its operation and has not cut, or whether it is in some other state. . Therefore, in this example, as shown in FIG. 1, a reflective photosensor 23 is provided as a bag detection sensor. This hoard sensor 23 is arranged at a position to detect when the bag 1) has reached the position where sewing by the sewing machine starts.

As shown in FIG. 4, while the photosensor 23 is detecting the presence of a bag, the photosensors 21 and 22 should normally be detecting when the yarn is moving, and the output of the photosensor 23 is detecting the presence of a bag. is the thread breakage detection period. The period from the time when the photo sensor 23 detects that there is no bag until the thread cutting and yarn swaying stops T seconds until the next time the presence of a bag is detected is when the photo sensor 21, 22 normally detects that the thread is stopped. This period should be the uncut defect detection period.

Next, an example of the electrical configuration of the present invention will be explained with reference to FIG. Photosensor 21, 22, 23 (7) Power sources 41, 42, 43 for the light emitting element are provided, and the photosensor 21,
The outputs of the light-receiving elements 22 and 23 are connected to amplifiers 44 and 4, respectively.
Amplified at 5.46.

Amplifiers 44 and 45 are AC amplifiers that block the DC component and amplify only the fluctuation component. Amplifier 46 is a DC amplifier. The outputs of amplifiers 44 and 45 are rectified and smoothed by rectifier circuits 47 and 48, respectively, and converted into direct current. Rectifier circuit 47
．． 48, each output of the amplifier 46 is sent to a sensitivity adjustment section 51
, 52, 53 to shaping circuits 54, 55, 56, and are shaped into high or low logic levels, respectively. Each output of the shaping circuits 54, 55, and 56 is supplied to a determination circuit 57.

In the determination circuit 57, the outputs of the shaping circuits 54 and 55 are supplied to an AND circuit 61 through inverters 58 and 59, respectively, and the output of the shaping circuit 56 is supplied to the AND circuit 61. The output of the shaping circuit 54゜55 is the OR circuit 6
2 to an AND circuit 63, and the output of the shaping circuit 56 is supplied to the AND circuit 63 through an inverter 64.

While the photo sensor 23 is detecting the presence of a bag, the output of the shaping circuit 56 is at a high level, while the output of the photo sensors 21 and 22 fluctuates when the thread is being fed out, and the output of the shaping circuits 54 and 55 is at a high level. At this time, the output of the AND circuit 61 is at a low level. However, if the feeding of the upper thread 16, the lower thread 17, or both is stopped while the photo sensor 23 is detecting the presence of a bag, the output of one or both of the shaping circuits 54 and 55 becomes low level in response to this. Therefore, AND circuit 6
The output of No. 1 becomes high level, the transistor 65 is driven, the light emitting diode 66 lights up, it is reported that the thread breakage has occurred, and the relay 67 is operated to take necessary measures.

- On the other hand, when the photo sensor 23 is detecting no bag, the shaping circuit 5
The output of 6 will be a low level, so the high level will be AND
If the photosensors 21 and 22 are not detecting yarn unwinding at this time, the output from the shaping circuit 54 is at a low level, and the output from the AND circuit 63 is at a low level. However, while detecting no bag, one of the shaping circuits 54 and 55,
Alternatively, when both outputs become high level, the output of the AND circuit 63 becomes high level, the transistor 68 is driven, the light emitting diode 69 lights up, an uncut defect is notified, and the relay 71 is activated to take necessary measures. will be done. The output of the shaping circuit 56 is passed through the delay circuit 72 to the transistor 73.
The transistor 73 remains conductive for T seconds in FIG. 4 even after the detection of the presence of a bag ends, and this transistor 73 short-circuits the pace emitter of the transistor 68. In the above description, the presence of a bag is detected by the photo sensor 23, but instead of this, it may be detected whether or not the sewing machine is in operation. In the above description, the bag is sewn directly with a sewing machine, but the present invention can also be applied to the case where the open end of the bag is covered with a sticker paper folded in half and the sewing machine is sewn over the sticker paper.

[Effects of the Invention] As described above, according to the present invention, it is possible to detect both poor sewing due to thread breakage of the sewing machine and poor sewing due to poor cutting of the sewing thread. Furthermore, the sensor detects whether the sewing thread is moving or not, and can perform accurate detection without malfunctions compared to a sensor that detects the tension of the sewing thread. Furthermore, both yarn breakage and uncut defects can be detected by the same sensor, and the configuration is simple.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a perspective view showing an example of a transmission type photo sensor, Fig. 3 is a waveform diagram showing an output example of the yarn fluctuation detection sensor, and Fig. 4 is a diagram showing an example of the output of the yarn fluctuation detection sensor. FIG. 5 is a time chart for detailed explanation and a block diagram showing an example of the electrical configuration in an embodiment of the present invention.

Claims (1)

[Claims] (1) In a device that machine sews the open end of a bag, the output changes depending on whether or not the thread is moving through each path of the upper thread and lower thread of the sewing machine that are supplied to the bag. A bag sewing machine sewing defect detector is provided with thread fluctuation detection sensors and a determination circuit for detecting sewing defects on the bag from the outputs of these sensors.