JPS6131196A - Detection of residual amount of bobbin thread - 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] The present invention relates to a method for detecting the remaining amount of bobbin thread in a sewing machine, which can automatically detect the remaining amount of bobbin thread in a sewing machine.

[Prior art]

As is well known, a sewing machine uses a single thread, an upper thread and a bobbin thread, and threads the bobbin thread onto the upper thread from the top of the fabric to the bottom with a needle to create a seam.This process is repeated to sew. It is something to do.

[The problem that the invention attempts to solve]

By the way, the spool with which the upper thread is wound is installed at the top of the sewing machine arm, and is a trap so that the sewist can directly observe how the spool decreases as the thread is fed out, but the bobbin thread is placed on a special bobbin. Since it is wound and stored in a bobbin case under the sewing machine bed, it cannot be observed from the outside.

For this reason, it is not possible to know in advance when the bobbin thread is used up, and the bobbin thread may run out during sewing. This will cause the stitches to fly out, which is fatal for sewing that requires delicate stitches, such as so-called decorative stitching. Therefore, if the thread runs out while sewing decorative stitches such as those described above, it is necessary to unravel the thread and start sewing again from the beginning of the stitch.

In view of the above circumstances, it is an object of the present invention to provide a method for detecting the remaining amount of bobbin thread, which can automatically detect the remaining amount of bobbin thread.

[Means to solve the problem]

In order to achieve the above object, the present invention is characterized in that the remaining amount of the lower thread is detected from the used amount of the upper thread. To be more specific, this invention was made based on the fact that in normal sewing, the amount of upper thread used is equal to the amount of lower thread used, and the thread rotates as the upper thread is let out. It is characterized in that the number of rotations of the rotating body is counted to determine the amount of upper thread used, and the remaining amount of lower thread is detected from the amount of used upper thread.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a partial sectional view of a sewing machine according to an embodiment of the present invention, in which an arm 2 is fixed on a bed 1.
A spool pin 3 is installed vertically at the top of the spool. Further, a support rod 4 is vertically provided at the center of the upper part of the arm 2, and this support rod 4
A pulley 5 is attached to the tip of the pulley 5 so as to be freely rotatable in the vertical direction. A bobbin 6 is loosely inserted into the spool pin 3, and the thread wound around the bobbin 6 is wound around a pulley 5 as an upper thread 7, and then passed through a thread hook 8 and passed through a sewing needle 9. ing. On the other hand, below the sewing needle 9 and inside the bed 1 is a bobbin case 102>! In this bobbin case 1O, a bobbin thread 11 is wound and an optical bobbin 12 is arranged. Then, as a motor (not shown) in the arm 2 rotates, the sewing needle 9 moves up and down, and the upper thread 7 and the lower thread 11 are paid out from the bobbin 6 and the bobbin 12, respectively. Sewing is performed using thread 11. In this case, the stitches of the adjusted sewing machine will be as shown in FIG. 2, and the amount of upper thread used and the amount of lower thread used will be the same.

Next, FIG. 3 is a block diagram showing the electrical configuration of a detection device according to an embodiment of the present invention.

A small magnet 13 is embedded in the periphery of the pulley 5, and a detection coil 14 is embedded near the periphery of the pulley 5.
or are placed. When the needle thread 7 is let out, the pulley 5 rotates and each time it passes the magnet 13 or the direct spinning of the detection coil 14, an induced voltage is excited in the detection coil 14, and a pulse-like Amplifier 15 as a signal
supplied to The amplifier 15 amplifies the pulsed signal to produce a signal P, which is supplied to the attenuation circuit 16 .

On the other hand, 17 is the thread count (unit of thread thickness) dial, which is set by the sewist and the cross-sectional area used becomes thinner in order from the smallest to the largest. For example, when comparing a yarn with a count of ≠θ and a yarn with a count of 1,20, the cross-sectional area of a yarn with a count of -0 is twice that of a yarn with a count of UO. On the other hand, no matter what the yarn count is, the bobbin 12 is always wound flatly around each flange as shown in FIG. μ. That is, no matter what yarn count is used, the total cross-sectional area A of the yarn wound around the bobbin 12 is always constant. Therefore, the total length of the bobbin thread 11 wound around the bobbin 12 is proportional to the thread count used, and in the case of ≠O-count thread, it is twice as long as the O-count thread. The attenuation circuit 16 attenuates the number of pulses of the nine signals P according to the count. For example, if the signal supplied from the thread count dial 17 indicates yarn count 10, set the pulse number to i/r:f If the yarn count is 4AO, set the pulse number to 30.
If it's the number, I'll go for JK. In this way, the reduction circuit 16 reduces the number of pulses of the signal P according to the yarn count, and reduces the number of pulses of the signal P to
A signal is supplied to the counter 18 such that the number of pulses from the beginning of use to the end of use is always a constant value C no matter what yarn count is used. The counter 18 counts the number of pulses of the signal supplied from the attenuation circuit 16 and supplies the trigger signal T to the display device 20 every time it counts a predetermined number of pulses set in advance. The counter 18 is also provided with a reset switch 19, and by turning on the reset switch 19, the counter 18 is reset, and at the same time, the counter 18 supplies a reset signal to the display device 20. Display. Device 2
0 is a plurality of display blocks 21.2 arranged in the - column.
1..., when the bobbin 12 is replaced with a new one and the bobbin thread 11 is not used at all, all display blocks 21 and 21 will light up ()oochi), while the lower When thread 11 is used and the power comes, all the lights go out (O
blood). That is, the display block 21 is fully lit by receiving the reset signal from the counter 19,
Then, each time the trigger signal T is supplied, the lights go out sequentially from the right side in Figure 1, and the remaining amount of the bobbin thread 11 is displayed.
The power came in and all the lights went out at 9pm.

Finally, the display device 20 is configured to allow a warning residual value to be set. This set includes display device 20
Rotate the nine remaining amount dial 22 provided in the
K is moved between the scales of O to ioo%. Then, when the display block 21 turns off from the right to @ and the pointer 23 reaches the indicated position, the buzzer 24 sounds.

In the above configuration, when the new bobbin 12 is set to 1, and the reset switch 19 is set to 6", the display block 2
1.21... all light up, indicating that there are x or 1 oots of yarn left.

First, the sewing person turns the thread count dial 17 to set the thread count to be used, and also turns the 1 remaining amount dial 22 to set the warning remaining amount value.

Next, the sewing machine is operated to start sewing. When sewing starts and the upper thread 7 is paid out, the pulley 5
rotates, 1 detection coil 1 every 7 rotations of Boo I75
4, an induced voltage is excited, which is amplified by an amplifier 15 and supplied as a pulsed signal P to a several-stage circuit 16.

In the reduction circuit 16, the number of pulses of the signal P or the thread count set by the thread count dial 17 is reduced.
This reduction result is counted by the counter 18.

Then, each time a predetermined number of pulses are input, the counter 1
8 outputs a trigger signal T, and the display blocks 21 of the display device 20 go out sequentially from the right side, informing the sewing person of the remaining amount of the bobbin thread 11. Then, when the remaining amount of the bobbin thread 11 reaches the warning remaining amount value set by the remaining amount dial 22, the buzzer 24 sounds. The sewing person is informed by this buzzer that the remaining amount of bobbin thread 11 has reached the warning value, and after continuing sewing until the specified position, stops the sewing machine and replaces the bobbin 12. do.

In this way, the remaining amount of the bobbin thread 11 can be directly read, so the remaining amount of the bobbin thread 11 can be directly read.
It is possible to detect in advance whether the lower thread 11 is used up, and to prevent the lower thread 11 from being used up during sewing.

In this embodiment, a combination of a magnet and a detection coil was used as a pulley rotation detection means, or other means such as a magnet and a Hall effect, a light emitting diode and a photodiode, a proximity switch, a microsinch, etc. Of course, it is okay to do so.

Alternatively, a pincushion in which one magnet is embedded may be used without providing a bobbin, and the rotation of the pincushion may be detected.

Alternatively, a digital display may be provided in place of the display block to digitally display the remaining amount.

Moreover, using this method, it is possible to judge whether or not the upper thread and lower thread are properly adjusted. In other words, if the upper and lower threads are not properly adjusted, there will be a difference in the amount of use of both threads. Therefore, if the actual remaining amount of the bobbin thread exceeds or is less than the amount displayed by the display device, it means that the upper thread and bobbin thread are not adjusted properly.

Next, another method of detecting the remaining amount of the lower thread from the used amount of the upper thread will be explained using FIG.

A light emitting diode 30 and a photodiode 31 are disposed facing each other in the middle of the travel path of the upper thread 7 via the upper thread 7. When the upper thread 7 is not running, the output of the photodiode 31 remains at a constant level (Ls in the figure). On the other hand, when the upper thread 7 starts running, the upper thread 7 vibrates, which disturbs the output of the photodiode 31 (L2 in the figure).

The shaping circuit 32 detects this disturbance in the output of the photodiode 31, and supplies a signal of 'H# (Ls in the figure) to one input terminal 33a of the AND gate 33 only during this period. The other input terminal 33bK of the AND gate 33 is supplied with a pulse signal of a predetermined frequency from a pulse generator (not shown), and as a result, the AND gate 33 generates one pulse when the upper thread 7 runs. A signal Q like this is output. The remaining amount of the bobbin thread can be detected by supplying this signal Q instead of the above-described nine signals P to the attenuation circuit 16 shown in FIG.

In addition, as yet another method, the input terminal 33aK of the AND gate 33 is set to level "H" or ", depending on the 1 on/1% off # of the starting switch of the motor that drives the sewing machine.
The remaining amount of the bobbin thread can be detected in the same way even if K is supplied so as to supply a signal that becomes "L".

〔Effect of the invention〕

As explained above, 1.According to the present invention, the number of revolutions of the rotating body that rotates as the upper thread is paid out is counted (to calculate the usage amount of the upper thread, and the remaining amount of the lower thread is calculated from the usage amount of the upper thread. Since the sewing machine detects the amount of bobbin thread, it is possible to detect the use of the bobbin thread in advance, thereby providing an advantageous effect such as preventing the bobbin thread from running out during sewing.

[Brief explanation of drawings]

FIG. 2 is a partial sectional view showing the configuration of a sewing machine according to an embodiment of the present invention, FIG. 1 is a sectional view showing a seam, and FIG. 3 is an electrical configuration of a detection device according to the embodiment. FIG. 3 is a block diagram showing the configuration of the main parts of a detection device related to another method of detecting the remaining amount of bobbin thread. Illustrated. 5... Pulley (rotating body), 7... Upper thread, 11... Lower thread, 13... Magnet, 1
4...Detection coil (13 and 14 above are rotation detection means).

Claims (1)

[Claims] In a lower thread remaining amount detection method of detecting the remaining amount of the lower thread of a sewing machine for sewing fabric while sequentially crossing the upper thread and the lower thread, a rotation detecting means is provided, and the rotation detecting means detects the amount of the lower thread remaining. The lower thread is characterized in that the rotation of a rotating body that rotates as the upper thread is let out is detected, the usage ratio of the upper thread is determined from the detection result, and the remaining amount of the lower thread is detected from the usage ratio. How to detect remaining thread amount.