JP2800417B2 - Sewing machine lower thread remaining amount detection 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 detecting a remaining amount of a lower thread of a sewing machine for detecting the remaining quantity of a lower thread wound on a bobbin.

[0002]

2. Description of the Related Art Conventionally, as an apparatus of this type, as described in Japanese Utility Model Application Laid-Open No. 61-180865, when the rotation of the outer hook stops, light is emitted from the light emitting element to the outer periphery of the bobbin shaft. There is known a lower thread remaining amount detecting device using a light detector which detects the reflected light with a light receiving element and detects the remaining amount of the lower thread based on the detected light.

[0003]

However, in such a lower thread remaining amount detecting device, the reflected light having a wavelength corresponding to the peak sensitivity of the element is detected using one light receiving element. In some cases, the amount of reflected light varies. Therefore, the value of the remaining amount of the lower thread detected based on the amount of the detected reflected light also varies. For example, even if the remaining amount of the lower thread is the same, the remaining amount of the lower thread is different if the thread color is different. Sometimes it was judged different.

Accordingly, an object of the present invention is to provide a lower thread remaining amount detecting device for a sewing machine capable of accurately detecting the lower thread remaining amount of a bobbin regardless of the color of the lower thread.

[0005]

SUMMARY OF THE INVENTION The present invention, which has been made to achieve the above object, has a window formed in a shuttle portion of a sewing machine, through which electromagnetic waves are transmitted, and provided at a predetermined position around the shuttle portion. An irradiating section that irradiates an electromagnetic wave to the lower thread winding portion of the bobbin housed in the shuttle section through the window section, and irradiates the electromagnetic wave with the irradiating section, so that the lower thread winding section of the bobbin passes through the window section. A receiving unit that receives electromagnetic waves reflected or transmitted from the sewing machine, and a lower thread remaining amount detecting device that detects the lower thread remaining amount of the sewing machine based on a reception state of the electromagnetic waves of the receiving unit. In the above, the irradiation unit is configured to be capable of irradiating electromagnetic waves including a plurality of wavelengths, and the wave receiving unit includes a plurality of elements that receive the electromagnetic waves radiated from the irradiation unit for each wavelength. It is characterized by that.

[0006]

In the bobbin thread remaining amount detecting device according to the present invention, the irradiating section irradiates an electromagnetic wave including a plurality of wavelengths to the bobbin lower bobbin winding section. Then, the plurality of elements provided in the wave receiving unit receive electromagnetic waves including a plurality of wavelengths reflected or transmitted from the bobbin winding portion of the bobbin for each wavelength.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 2 is a schematic configuration diagram showing a configuration of the lower thread remaining amount detection device of this embodiment and an assembled state of the device to a sewing machine.

As is well known, the needle thread A is inserted into the bed 1 of the sewing machine in cooperation with the needle 2 which can move up and down through the needle plate 1a.
And a hook portion 3 for forming lockstitches on the work cloth B is provided. The shuttle portion 3 includes an outer shuttle 4 that can rotate in synchronization with the vertical movement of the needle 2, and the outer shuttle 4 has a sword tip 4 a and a notch 4 b. The inner hook 5 is held in a stationary state in the outer hook 4, and the bobbin case 6 is removably positioned and mounted in the accommodating portion 5 a of the inner hook 5. The bobbin case 6 includes a hollow shaft portion 7a around which the lower thread C is wound and a pair of flange portions 7b provided at both ends of the hollow shaft portion 7a. The bobbin 7 is detachably and rotatably mounted.

Therefore, in the lower thread remaining amount detecting device of this embodiment,
In the peripheral wall of the inner pot 5 and the bobbin case 6, windows 8, 9 that are provided to face the cutouts 4 b of the outer pot 4 when the needle 2 is at a predetermined needle position (for example, a needle position). In this way, a passage that can communicate with the inside and outside of the shuttle portion 3 through the notch portion 4b and the windows 8 and 9 at a predetermined needle position is formed in advance, and the bobbin thread C wound around the bobbin 7 is formed through this passage. A detection unit 10 is provided for irradiating light and detecting the remaining amount of the lower thread from the reflected light.

As shown in FIG. 1, the detecting section 10 is disposed at a position around the hook section 3 opposite to the windows 8 and 9 and irradiates the lower thread C with light. A wave receiving unit 1 disposed at a position opposed to 8, 9 for receiving reflected light from the lower thread C
The irradiation unit 17 and the wave receiving unit 19 are provided with a screw 15 on a support portion 13 a protruding from the sewing machine main body 13.
a fixed to the support 15 attached.

The irradiating section 17 and the wave receiving section 19 are covered by a case 21 having a light transmitting section at the tip.
7 are isolated so that the light rays emitted from 7 do not directly enter the wave receiving unit 19.

As shown in the side sectional view of FIG. 1, the irradiating section 17 includes light emitting elements 17r, 17g, and 17b for individually irradiating the lower thread C with ternary light beams. Are light receiving elements 19r and 19 for receiving each reflected light from the lower thread C.
g, 19b. Each of the elements 17r to 19r
A lens is provided integrally at the tip of b.

In the detection unit 10 configured as described above, when the light emitting elements 17r to 17b are driven, spot lights are individually emitted toward the bobbin 7 in the shuttle unit 3. Then, for example, when the notch 4b of the outer shuttle 4 matches the respective windows 8, 9 of the inner shuttle 5 and the bobbin case 6, corresponding to the needle upper position of the needle 2, spot light from the light emitting elements 17r to 17b is emitted. ,
The lower thread C wound around the bobbin 7 through the notch 4b and the windows 8 and 9 is irradiated, and the reflected light of the lower thread C is
9 and the notch 4b, and is incident on the light receiving elements 19r to 19b.

When the notch 4b of the outer hook 4 does not face the windows 8 and 9, the light emitted from the light emitting elements 17r to 17b is almost completely reflected by the side of the outer hook 4. Since the side surface of the outer hook 4 is disposed very close to the light emitting elements 17r to 17b, the reflection angle of each light beam increases, and almost no light enters the light receiving elements 19r to 19b.

Next, the light emitting elements 17r, 17g, 17b
Indicates that the peak of each emission wavelength is 700 nm (red), 5
The light receiving elements 19r, 19g, and 19b have peak sensitivities near 700 nm, 550 nm, and 490 nm, respectively.
Therefore, for example, the light emitting element 17r irradiates the lower thread C with red light, and the light receiving element 19r adjacent to the lower thread C generates a detection signal corresponding to the amount of red light reflected by the lower thread C.
Similarly, the light emitting elements 17g and 17b irradiate the lower thread C with green light or blue light, and the light receiving elements 19g and 19b adjacent thereto irradiate the lower thread C with green light or blue light reflected by the lower thread C. A detection signal corresponding to the light amount is generated.

Therefore, the lower thread detecting device of this embodiment is shown in FIG.
As shown in the figure, the detection signals of the respective light receiving elements 19r to 19b are
An electronic control circuit (ECU) 2 mainly including a known microcomputer via an A / D converter 23
5 are individually input. In addition to the detection signals of the light receiving elements 19r to 19b, operation signals of the input panel 27 are input to the ECU 25, and the ECU 25 outputs drive signals to the display device 29 and the warning device 31 based on these signals. I have.

In the bobbin thread remaining amount detecting device of the present embodiment constructed as described above, when the bobbin thread C is sufficiently left on the bobbin 7 and the hollow shaft portion 7a is not exposed, the bobbin thread C is Since the light beam corresponding to the opposite color is absorbed, the light receiving element 19r
At least one of the detection signals of
The value is significantly lower than when light beams from 7r to 17b are directly received.

For example, when the color of the lower thread C is red, the light emitting element 1
The red light emitted from 7r is well reflected by the lower thread C, and the detection signal of the light receiving element 19r shows a high value, but the green light and the blue light emitted from the light emitting elements 17g and 17b are absorbed by the lower thread C. Therefore, the light receiving elements 19g and 19g
The detection signal of r shows a low value.

Next, the lower thread C is gradually consumed and the hollow shaft portion 7a
Is exposed, since the bobbin 7 has good metallic luster, the light beam irradiated on the portion where the hollow shaft portion 7a is exposed is almost completely reflected. Therefore, the light receiving element 1
All of the detection signals 9r to 19b gradually show higher values. Further, when the lower thread C is completely consumed and the hollow shaft portion is completely exposed, the light emitted from the light emitting elements 17r to 17b is almost completely reflected and enters the light receiving elements 19r to 19b, and the light emitted from the light receiving elements 19r to 19b The detection signal has substantially the same value as when the light beams from the light emitting elements 17r to 17b are directly received.

Then, the ECU 25 sets the light receiving elements 19r-1
9b is compared with a predetermined value corresponding to the remaining amount of the lower thread for which the bobbin 7 is to be replaced, and the light receiving elements 19r to 19b are compared.
When any of the detection signal values exceeds the predetermined value, a decrease in the remaining amount of the lower thread C is detected. Hereinafter, the remaining amount decrease detection processing performed by the ECU 25 will be described with reference to the flowchart of FIG. This process is started when a pedal (not shown) for starting sewing of the work cloth B is depressed.

When the processing is started, first, in S11, each detection signal S generated by the light receiving elements 19r, 19g, 19b is generated.
The values of r, Sg, and Sb are read. In S13, the color of the lower thread C is calculated by calculating the ratio of the detection signals Sr, Sg, and Sb. In S15, a drive signal is output to the display device 29 to display the detected color of the lower thread C. I do.

Subsequently, when the flow shifts to S17, the input panel 2
In step S19, a drive signal is output to the display device 29 to display the set remaining thread amount M, which is set in step S7. S17
If the lower thread remaining amount M has not been set in step, M = 0 is set, and the routine goes to S19. Next, in S21, the light receiving element 1 actually measured in advance at various lower thread remaining amounts using the reference thread is used.
From the data of the detection signals 9r to 19b, the data corresponding to the set lower thread remaining amount M is read out, and based on this, a reference value Sα as a criterion for determining the remaining lower quantity of the lower thread C is set.

In the following S23, each of the detection signals Sr to Sb is compared with a reference value Sα, and if it is determined that any of the detection signals Sr to Sb is lower than the reference value Sα, the detection signal Sr is returned in S25. , Sg, and Sb after reading the values of
Then, if it is determined that all of the detection signals Sr to Sb exceed the reference value Sα, the process proceeds to S27.
That is, in the loop formed by S23 and S25,
When the hollow shaft portion 7a is exposed, the detection element 19r
The control waits until all of the detection signals Sr to Sb of the signals Sr to Sb exceed the reference value Sα set in S21.

In S27, the ECU 25 outputs a warning device 31 drive signal, warns the operator that the bobbin 7 needs to be replaced, and terminates the process. The warning device 31 is a known device including a buzzer, a lamp, and a driving circuit thereof.

In the bobbin thread remaining amount detecting device thus constructed in this embodiment, the ternary colors of red, green and blue are emitted from the light emitting elements 17r, 17g and 17b and reflected by the lower thread C. Are received individually by the light receiving elements 19r, 19g, and 19b, so that the amount of the reflected light for each color is detected by the detection signal Sr,
It can be detected as Sg and Sb. Then, by comparing the values of the detection signals Sr, Sg, and Sb with a reference value Sα set corresponding to the remaining amount M of the lower thread for which the bobbin 7 is to be replaced, regardless of the color of the lower thread C, It is possible to accurately detect whether or not the remaining amount of the lower thread C wound around the bobbin 7 is less than the remaining thread amount M. Further, in the lower thread remaining amount detecting device of this embodiment, the color of the lower thread C is detected based on the ratio of the detection signals Sr, Sg, Sb. By confirming whether or not the color of the thread C matches, it is also possible to confirm whether or not the lower thread remaining amount detecting device has malfunctioned.

In this embodiment, one light emitting element 17r
The light receiving elements 19r to 19b are provided one by one to the light receiving elements 19r to 19b, and the remaining amount of the lower thread is detected by detecting the amount of each reflected light from the lower thread C.
As described in No. 91, two light-receiving elements provided at different positions are provided for one light-emitting element, and the reflection angle at which each light ray is reflected by the lower thread is measured. The amount may be detected. In this case, since the distance from the light receiving element to the lower thread surface is directly detected, a non-glossy plastic bobbin can be used.
Even when the hollow shaft portion of the bobbin is not exposed at all, the remaining amount of the lower thread wound on the bobbin can be detected.

In this embodiment, three types of light emitting elements 17 are individually provided as irradiation units for three types of electromagnetic waves.
r, 17g, and 17b, and three types of light receiving elements 19r, 19g, and 19b as the wave receiving unit are provided.
The number of wavelengths of the electromagnetic wave used for detection may be any type as long as it is a plurality of types. If a light-emitting element in which the wavelength of the generated electromagnetic wave is distributed over a wide range is used, the irradiation unit can be configured with one element. Furthermore, if filters for selectively transmitting electromagnetic waves of a specific wavelength are provided on the surfaces of a plurality of light receiving elements for different wavelengths, the wave receiving section can be constituted by one type of light receiving element.

Further, in this embodiment, the color of the lower thread C and the remaining amount of the lower thread C are individually calculated, but the detection signal of each light receiving element is calculated based on the calculated color of the lower thread. The lower thread remaining amount can be calculated based on the corrected detection signal.

[0029]

As described in detail above, in the bobbin thread remaining amount detecting device of the present invention, the plurality of elements provided in the wave receiving section are formed by the plurality of bobbin bobbin lower bobbin thread reflected or transmitted. Since the electromagnetic wave including the wavelength is received for each wavelength, by detecting the lower thread remaining amount based on the receiving state of each element, the lower thread remaining amount of the bobbin can be accurately determined regardless of the lower thread color. Can be detected.

[Brief description of the drawings]

FIG. 1 is a side cross-sectional view illustrating a configuration of a lower thread remaining amount detection device according to an embodiment and an assembled state of the device to a sewing machine.

FIG. 2 is a schematic configuration diagram illustrating a configuration of a lower thread remaining amount detection device according to an embodiment and a state of being assembled to a sewing machine.

FIG. 3 is a flowchart illustrating a remaining amount decrease detection process performed by the lower thread remaining amount detection device according to the embodiment;

[Explanation of symbols]

3 ... Hook part, 4 ... Outer hook, 4b ... Notch part, 5 ... Inner hook, 6 ... Bobbin case 7 ... Bobbin, 8, 9 ... Window part, 10 ... Bottle thread detector 17r, 17g, 17b ... Light emitting element 19r, 19
g, 19b: light receiving element 25: ECU

Claims (1)

(57) [Claims] 1. A window formed in a shuttle portion of a sewing machine and transmitting electromagnetic waves, and provided at a predetermined position around the shuttle portion.
An irradiating unit that irradiates an electromagnetic wave to the bobbin winding portion of the bobbin housed in the shuttle through the window, and irradiates the electromagnetic wave with the irradiating unit so that the bobbin bobbin winding passes through the window. A receiving unit for receiving electromagnetic waves reflected or transmitted from the receiving unit, and a lower thread remaining amount detecting device for the sewing machine that detects a lower thread remaining amount of the sewing machine based on a reception state of the electromagnetic waves of the receiving unit In the above, the irradiation unit is configured to be capable of irradiating an electromagnetic wave including a plurality of wavelengths, and the receiving unit includes a plurality of elements that receive the electromagnetic waves irradiated from the irradiating unit for each wavelength. A lower thread remaining amount detecting device for a sewing machine, comprising: a sewing machine;