JPS63132693A - Bobbin thread residual amount 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 The present invention uses a light-reflecting device to warn the operator that the bobbin thread wound on the bobbin is running low and to stop the next cycle. This invention relates to a bobbin thread remaining amount detection device.

Ibarao Nasue Conventionally, this type of bobbin thread remaining amount detection device irradiates light from a light emitting part to the bobbin in the hook, and detects the reflected light from the bobbin thread wound around the bobbin by a light receiving part. When the bobbin thread runs out and the reflected light from the bobbin shaft is detected by the light receiving section, the photodetector detects that the reflected light has changed, thereby detecting the bobbin thread wound around the bobbin in the hook. It was designed to detect the remaining amount.

However, in the conventional bobbin thread remaining amount detection device configured as described above, in order to bring the light emitting part and the light receiving part close to the hook, there is a possibility that the lubricating oil from the hook may be splashed or fall off from the thread or the sewing material. The light emitting part and the light receiving part are affected by light blocking due to cotton dust, etc., resulting in a decrease in the detected photocurrent. Since thread is used, there is a difference in the reflected photocurrent depending on the color, and it is extremely difficult to detect the amount of bobbin thread remaining in the bobbin just by the magnitude of the photocurrent generated by the photoelectric element, which consists of a light emitting part and a light receiving part. There was a problem.

. In order to solve the above-mentioned problems, the present invention for fortune-telling has a light-emitting section that illuminates the bobbin in the hook, and a light-receiving section that detects the bobbin thread wound around the bobbin or the reflected light from the shaft portion of the bobbin. a first calculation device that calculates a ratio between a signal detected by the light receiving portion of the photodetector and a reflected signal detected one time or several times before; a second calculation device that calculates the ratio between the output of the calculation device and a predetermined constant value; and a second calculation device that calculates the ratio between the output of the calculation device and a predetermined constant value, and a It is characterized by comprising a determining means for determining the presence or absence of a wound bobbin thread.

■According to the present invention, the ratio of the reflected signal detected from the reflected light from the bobbin to the reflected signal detected one or more times before is calculated, and the signal of that ratio is set to a predetermined setting value. The remaining amount of bobbin thread is detected by detecting whether the amount of bobbin thread is higher or lower, so if the reflected light from the bobbin is constant, it is necessary to apply lubricating oil to the light emitting part or the light receiving part of the photodetector. Even if the light changes due to adhesion of droplets or cotton dust, there is almost no difference from the reflected signal detected one time or several times before, so the change in light amount due to changes in external conditions The presence or absence of the bobbin thread is not determined in this case, but when the bobbin thread is removed and the reflected light from the shaft is detected, the bobbin shaft clearly changes from the reflected light from the bobbin thread. Since the remaining amount of the bobbin thread is detected by detecting only the reflected light from the bobbin thread, there is no malfunction and the remaining amount of the bobbin thread can be reliably detected.

Figure 1 is a partially sectional plan view of a bobbin thread remaining amount detection device according to an embodiment of the present invention, and Figure 2 is a side view of Figure 1, showing a sewing machine frame 1.
A part of a coaxial optical fiber 2 is fixed to the optical fiber 2, and a light emitting part 3 is provided oppositely to one end 2a of the optical fiber 2.
A light receiving section 4 is provided facing the other end 2b, and a light emitting/receiving end 2C of the optical fiber 2 is provided facing the through hole 7 of the bobbin case 6 of the horizontal hook 5. This through hole 7 is provided on the side surface of the bobbin case 6 as shown in FIG. The light emitting/receiving end 2C is provided so that the light reflected from the reflective tape 9 attached to the substantially central portion of the shaft portion 8a can be detected through the through hole 7.

In this bobbin thread remaining amount detection device, the light emitted from the light emitting unit 3 is guided from one end 2a of the optical fiber 2 to the light emitting/receiving end 2C, and is irradiated from the light emitting/receiving end 2C into the through hole 7 of the bobbin case 6. , the thread wound around the bobbin 8 inside the bobbin case 6 or the shaft portion 8a of the bobbin 8 is irradiated. The reflected light from the thread or shaft portion 8a is guided from the light emitting/receiving end 2C of the optical fiber 2 to the other end 2b, and is received by the light receiving portion 4.

The reflected light received by the light receiving section 4 is input to the A/D converter 10 and converted into a digital signal as shown in FIG. 4, and this converted digital signal DX,l is sent to the first computing unit. 11 and register 12. This register 1
2, when the next digital signal is input, the digital signal DX, which was input one time before, is output and input to the first arithmetic unit 11. The first arithmetic unit 11 is A/
The ratio between the signal Dxl directly input from the D converter 11 and the previous signal DX input from the register 12 is calculated. Here, when there is a bobbin thread on the bobbin 8.

Since there is almost no difference between the signal DX directly input from the A/D converter 11 and the previous signal DX input from the register 12, the output of the first arithmetic unit 11 is "1". become. The output from the first arithmetic unit 11 is input to the second arithmetic unit 13, and the set value K is input from the setter 14 to the second arithmetic unit 13, and the first a! The ratio between the output from the setter 11 and the set value from the setter 14 is taken. In this case, the output is "1" and the set value = 1.
25, the judgment value A = L / K = 1 /
1.25=0.8. Here, the determiner 15 determines that A≧1
Since it is set to output an output when .

Next, when the thread wound around the bobbin 8 runs out and the light receiving section 4 detects the reflected light from the reflective tape 9 of the shaft section 8a of the bobbin 8, the reflected signal detected by the light receiving section 4 becomes high, and therefore , the digital signal DX input to the first arithmetic unit 11,
and the previous digital signal Dx passed through the register 12, -
Since the output of the ratio with 1 is rl, 25J, the output A of the second arithmetic unit 13 becomes A≧1, and therefore the 1 determiner 1
4 outputs an output, and it can be determined that the thread wound on the bobbin 8 is no longer present.

This embodiment calculates the ratio between the signal that detects the winding state of the thread on the bobbin 8 and the signal detected one time before, and compares this ratio with a preset value. Regardless of the type or color of the thread, it is possible to detect when the thread wound around the bobbin 8 has run out, and even if dust or dirt adheres to the light emitting/receiving end 2c of the optical fiber 2. Since there is almost no difference between the detected signal and the previously detected signal, detection is possible even if this dirt or dust is attached, and the presence or absence of thread can be reliably detected.

In addition, in the above embodiment, by providing the reflective tape 9 on the shaft portion 8a of the bobbin 8, the thread disappears from the bobbin 8.
When the shaft portion 8a of the bobbin 8 is exposed, the exposure reflected light is increased, but conversely, a non-reflective portion may be provided in the shaft portion 8a of the bobbin 8 to make the exposure reflected light “O”.

FIG. 5 is a block diagram of a bobbin thread remaining amount detection device according to another embodiment of the present invention, in which the thread of the bobbin 8 or the reflected light from the shaft portion 8a is detected by the light receiving section 4 of the photodetector, and the A/D After inputting it to the converter 10 and converting it into a digital signal DX, the central processing unit CPU
16, and stores it in the read/write memory RA old 7, and calculates the comparison between this stored digital signal DX, 1 and the digital signal Dx11-0 stored one time or several times ago, and reads and writes it into the read/write memory RAM 17. The determination value A is stored in the central processing unit CP [
J16 performs the calculation, and the central processing unit CPU16 determines whether A≧1 as described above, and displays the display 1.
8 may be displayed.

In the above embodiment, an example was explained in which a coaxial optical fiber 2 was used as a photodetector, but a photodetector that emits light and receives light separately may be used.

Effects of the Invention As is clear from the above description, the present invention calculates the ratio of the reflected signal detected from the reflected light from the bobbin to the reflected signal detected one or more times before, and further calculates the ratio of the reflected signal detected one or more times before. The remaining amount of bobbin thread is detected by detecting whether the signal is higher or lower than a predetermined set value, so if the reflected light from the bobbin is constant, the light emitted by the photodetector Even if the light changes due to lubricant droplets or cotton dust adhering to the sensor or the light-receiving section, there is almost no difference from the reflected signal detected one time or several times before, so it is possible to detect the external situation. The presence or absence of the bobbin thread is not determined by the change in the amount of light that changes due to the change in the amount of light, but the light reflected from the bobbin shaft is detected when the bobbin thread disappears, so there is a clear change in the light reflected from the bobbin thread. Since the amount of bobbin thread remaining is detected by detecting only the reflected light, it can be detected regardless of the type of thread or the color of the thread, and even if there is dust or dirt on it, malfunctions will not occur. This has the advantage that the remaining amount of the bobbin thread can be detected reliably.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional plan view of a bobbin thread remaining amount detecting device according to an embodiment of the present invention, FIG. 2 is a partially sectional side view of FIG. 1, and FIG.
The figures are side views of the bobbin case and bobbin in Figures 1 and 2, Figure 4 is a block diagram of a circuit that processes the optical signal detected by the photodetector of the embodiment of the present invention, and Figure 5 is a side view of the bobbin case and bobbin in Figures 1 and 2. , is a block diagram of a circuit for processing an optical signal detected by a photodetector according to another embodiment of the present invention. ■...Sewing machine frame, 2...Optical fiber, 3...
... Light emitting section, 3... Light receiving section, 5... Horizontal pot, 6...
・Bobbin case, 7...Through hole, 8...Bobbin, 9・
...Reflective tape, 10...A/D converter, 11...
1st arithmetic unit, 12... register, 12... register, 13... second arithmetic unit, 14... setting device, 1
5... Judgment device.

Claims (5)

[Claims] (1) A photodetector consisting of a light-emitting part that illuminates the bobbin in the hook, and a light-receiving part that detects the bobbin thread wound around the bobbin or the reflected light from the shaft of the bobbin, and the light-receiving part of the photodetector. a first calculation means for calculating the ratio between the signal detected by the section and the reflected signal detected one time or several times before; and a ratio between the output of the first calculation means and a predetermined constant value. and determining means for determining whether there is a bobbin thread wound around the bobbin based on whether the output of the second calculating means is higher or lower than a predetermined set value. Lower thread remaining amount detection device. (2) The bobbin thread remaining amount detecting device according to claim 1, characterized in that a reflective tape is attached to the shaft portion of the bobbin. (3) The bobbin thread remaining amount detecting device according to claim 1, characterized in that a mirror-finished portion is provided on the shaft portion of the bobbin. (4) The bobbin thread according to claim 1, characterized in that the photodetector is composed of an optical fiber having one end facing the hook and the other end split to face a light emitting part and a light receiving part, respectively. Remaining amount detection device. (5) The bobbin thread remaining amount detecting device according to claim 3, wherein the surface of one end of the optical fiber facing the hook is covered with a thin transparent film.