JPH06269589A - Cloth end detector - Google Patents

Abstract

PURPOSE:To enable a worker to ocularly confirm the detection position in a cloth end detection device for detecting the cloth end position on the upper side of superposed two sheets of cloth. CONSTITUTION:This device comprises a first projector 1 to generate shadow at a cloth step part, a second projector 2 to generate no shadow thereat, a third projector 3 to receive the reflection light against a cloth part emitted from each projector 1, 2, and a computation unit to have a cloth step part output through comparison with respective reflection light amounts received by the light reception unit 3 when each projector 1, 2 blinks indivisually. In this device, a visible light beam emmission diodes are arranged on each light receiving element 8, 9 of the light receiving unit 3 so as to blink upon stoppage of cloth feeding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine for detecting an upper cloth edge position of two layers by detecting it as a cloth step portion.

[0002]

2. Description of the Related Art The present applicant has developed a cloth edge detecting device shown in FIG. 6 and filed an application for it (Japanese Patent Application No. 4-115340).
issue). The cloth edge detecting device includes a first floodlight 1 that creates a shadow 13 on the cloth step portion and a second projector 1 that does not create a shadow 13 on the cloth step portion.
Projector 2, receiver 3 for receiving the reflected light from the cloth projected by each projector 1, 2, and the amount of each reflected light received by receiver 3 when each projector 1, 2 individually blinks. And an arithmetic unit for obtaining the cloth step section output.

[0003]

The detection position in the above-described cloth edge detecting device is estimated by the operator visually observing the light projected from each of the projectors 1 and 2. However, in order to prevent a malfunction caused by the cloth moving up and down and the amount of light received by the light receiver 3 changing, the light projecting range of each of the light projectors 1 and 2 is widened to some extent, so that the detection position can be accurately known. Is difficult. Further, when infrared rays are used for the light projected from the respective projectors 1 and 2 in order to increase the sensitivity of the light receiver 3, the detection position can hardly be visually observed, and the sewing manufacturer is anxious. become.

It is an object of the present invention to enable a worker to accurately visually check the detection position in a cloth edge detection device that detects the upper cloth edge position when two sheets are stacked.

[0005]

In order to achieve the above object, a cloth edge detecting device of the present invention comprises a first light projector for forming a shadow on a cloth step portion and a second light projector for not forming a shadow on a cloth step portion. And a receiver that receives the reflected light from the cloth of the light projected from each projector and the amount of each reflected light that the receiver receives when each projector individually blinks to obtain the cloth step output. It is composed of an arithmetic unit, and a visible light emitting diode which is turned on when the cloth feed is stopped is arranged on the light receiving element of the light receiver.

[0006]

[Operation] In the cloth edge detecting device configured as described above, when cloth feeding is stopped, the visible light emitting diode is turned on, and the shadow of the light receiving element (detection position) is imaged on the needle plate. In the surrounding area, there is a bright area where light coming from around the light receiving element is collected. Therefore, it is possible to clearly see the presence of the shadow (detection position) on the bright portion.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the cloth edge detecting device of the present invention will be described with reference to FIGS.

This cloth edge detecting device is composed of a first light projector 1, a second light projector 2, a light receiver 3 and an arithmetic unit shown in FIG. 4, which is arranged above the needle plate 4 of the sewing machine. The first floodlight 1 is provided in the sewing machine head, which is in front of the cloth edge detection position in the traveling direction of the cloth, in order to form the shadow 13 at the cloth edge. The second light projector 2 is provided outside the sewing machine head on the front side in the traveling direction of the cloth with respect to the cloth edge detection position, and causes reflection of light without shadow even if the cloth edge exists. Light receiver 3
Is placed at an appropriate height capable of projecting an image of the cloth on the cloth edge detection position.

Each of the projectors 1 and 2 comprises an infrared light emitting diode 5 and an optical lens 6 (convex lens) as a light source. Infrared rays are projected from the infrared light emitting diode 5 at the time of cloth feeding, and are collected in the irradiation area 7 on the surface of the needle plate 4 by the optical lens 6. Since infrared rays have a longer wavelength than visible rays and are not easily affected by obstacles or the like, the amount of light received by the light receiver 3 increases and the sensitivity as a sensor improves.

The light receiver 3 is housed in a transparent case, and the first photodiode 8 and the second photodiode 8 for converting the amount of received light into an amount of electricity.
Photodiode 9, visible light emitting diode 14 provided above them, and optical lens 10 (convex lens)
Composed by. The light quantity of the first detection area 11 on the needle plate 4 surface projected from the infrared light emitting diode 5 and condensed by the optical lens 10 is the first photodiode 8, and the light quantity of the second detection area 12 is the second photo area. Each is detected by the diode 9. However, the first detection area 11 and the second detection area 1
The first floodlight 1 and the second floodlight 2 are arranged so that the cloth step portion is positioned in the middle of 2.
It is assumed that the directions of the light projector 2 and the light receiver 3 are adjusted. The visible light emitting diode 14 projects visible light when the cloth feeding is stopped and turns off when the cloth feeding is stopped.

Visual recognition of the detected position (indication of the detected position) and detection of the cloth step portion are performed as follows. The detection position instruction (lighting of the visible light emitting diode 14) and the detection of the cloth step portion can be alternately repeated.

When the cloth feed is stopped and the needle position detector 17 provided on the main shaft of the sewing machine detects that the needle is below the needle plate surface 4, the visible light emitting diode 14 is turned on. Since the visible light emitting diode 14 is arranged on the central axis of the light receiver 3, the shadow 15 of the photodiodes 8 and 9 is imaged on the needle plate 4 by the optical lens 10.
The center of the shadow 15 is the boundary between the first detection area 11 and the second detection area 12 described above, and is the position where the cloth steps are aligned, that is, the detection position. Further, 16 in FIG. 3 is a bright portion where light coming from around the photodiodes 8 and 9 is collected. This bright portion 16 is significantly smaller than the illuminated area 7.
Since the presence of the shadow 15 on the bright portion 16 can be clearly seen, the detection position can be seen accurately. At this time, the output of the sensor circuit 25 is invalidated to prevent malfunction as described later.

On the other hand, when the cloth is fed and the needle position detector 17 detects that the needle is above the needle plate surface 4, the visible light emitting diode 14 is turned off and the cloth step is detected. Be seen. First, the first light projector 1 that produces a shadow 13 on the stepped portion of the cloth is turned on, and the first detection area 11 and the second
The ratio of the amount of light in the detection area 12 is obtained, and then the second projector 2 that does not generate the shadow 13 is turned on, and the first detection area 11 at that time is turned on.
Then, the ratio of the light amount of the second detection area 12 is obtained, and finally, the value obtained by dividing the former value by the latter value is obtained as the output of the cloth step section. For details of this calculation, refer to the above-mentioned application (Japanese Patent Application No. 4-11534).
No. 0).

Next, the circuit shown in FIG. 4 will be described.

In this circuit, a driver 19, a first driver 21,
The second driver 22 and the AND gate 28 operate. The function of each part is as follows. The driver 19 turns on and off the visible light emitting diode 14, and the first driver 2
1 turns on and off the first floodlight 1, and the second driver 22 turns on and off the second floodlight 2. The first amplifier 23 amplifies the signal of the first photodiode 8, and the second amplifier 24 amplifies the signal of the second photodiode 9. The sensor circuit 25 is composed of a sample-and-hold and arithmetic circuit, and is a ratio of the light amounts of the first detection area 11 and the second detection area 12 when the first light projector is turned on, and the first detection when the second light projector 2 is turned on. A value obtained by dividing the ratio of the light amounts of the area 11 and the second detection area 12 and the former value by the latter value is calculated. The comparator 26 compares the output value of the sensor circuit 25 with the value of the sensitivity adjustment volume 27, outputs 0 (no cloth step) when the detection value> the sensitivity adjustment value, and when the detection value ≦ the sensitivity adjustment value. Outputs 1 (with cloth step). AND gate 28
Is 1 from both the needle position detector 17 and the comparator 26.
Is output when is output. Data latch 29
Holds the output of the AND gate 28 and outputs the cloth section output.

When the cloth feed is stopped and the needle is below the needle plate surface 4, the output of the needle position detector 17 becomes 0, the driver 19 is operated by the inverter 18, and the visible light emitting diode 14 is turned on. Therefore, the photodiodes 8 and 9 receive a large amount of light, and the output of the comparator 26 as the sensor circuit 25 becomes meaningless. However, as described above, since the value of the needle position detector 17 at this time is 0, the output of the AND gate is 0. By holding this value in the data latch 29, the sensor circuit 25 becomes meaningless. Output can be disabled.

When the cloth is fed and the needle is above the needle plate surface 4, the output of the needle position detector 17 is 1, and the driver 19 is not operated by the inverter 18, so that the visible light emitting diode 14 is not turned on. Therefore, the sensor circuit 25 operates normally, and the comparator 2
The output of 6 is 1 (when there is a cloth step portion) or 0 (when there is no cloth step portion). As described above, since the value of the needle position detector 17 at this time is 1, the output of the AND gate 28 is 1, 0, that is, the value with the cloth step portion and the value without the cloth step portion, respectively. Since it is held by the latch 29, it becomes the cloth step output.

The above points are summarized as shown in the flow chart of FIG.

[0019]

Since the present invention is configured as described above, it has the following effects.

That is, since the visible light emitting diode provided on the light receiving element is turned on and the shadow of the light receiving element is projected on the needle plate surface, even when infrared rays are used for the light projected from each projector, the light is accurately projected. The detection position can be visually recognized. Therefore, the position of the sensor can be easily adjusted. Further, since the optical axis of the light received at the time of detecting the cloth edge and the optical axis of the light emission of the detection position designating operation are the same, the designated position shift due to the floating of the sewing cloth does not occur. Further, by alternately repeating the cloth edge detection and the visible light emitting diode lighting, it is possible to perform sewing while confirming the detection position.

[Brief description of drawings]

FIG. 1 is a perspective view showing a mounting position of a cloth edge detecting device of the present invention in a sewing machine.

FIG. 2 is a side view illustrating the principle of the cloth edge detecting device according to the present invention during cloth feeding.

FIG. 3 is a side view for explaining the principle of the cloth edge detecting device of the present invention when cloth feeding is stopped.

FIG. 4 is a block diagram of a cloth edge detecting device of the present invention.

FIG. 5 is a flowchart showing a procedure for visually recognizing a detection position in the cloth edge detecting device of the present invention.

FIG. 6 is a side view of a conventional cloth edge detecting device.

[Explanation of symbols]

 1 1st light emitter 2 2nd light emitter 3 Light receiver 8 1st photodiode (light receiving element) 9 2nd photodiode (light receiving element) 14 Visible light emitting diode

Claims (1)

[Claims] 1. A first light projector that creates a shadow on a cloth step portion, a second light projector that does not create a shadow on the cloth step portion, and a light receiver that receives reflected light from the cloth of the light projected from each light projector. And a calculation unit that obtains the cloth step output by comparing the amount of each reflected light received by the light receiver when each light emitter individually blinks, and the visible light that lights up when the cloth feed is stopped on the light receiving element of the light receiver. A cloth edge detector with a light emitting diode.