JPS5922941Y2 - Weld line confirmation device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for detecting a welding line with a sensor and checking whether a welding torch is at a predetermined position with respect to the welding line of a workpiece. be.

Welding is performed by fixing the object to be welded and moving the welding I/-ch along a predetermined trajectory, or by fixing the welding torch and rotating or moving the object in a straight line. Therefore, in automatic welding equipment that performs welding by moving the welding torch and the workpiece relatively, the welding I-ch is at a mechanically determined position, so the welding torch's drawing relative to the workpiece is The trajectory will draw a fixed trajectory determined with the welding device as a reference.

On the other hand, the weld line of the object to be welded is not necessarily in the correct position, and some deviation occurs.

If this position is too significant, the locus of the welding torch and the welding line will be too far apart, making it impossible to obtain a satisfactory welding result.

As a countermeasure for this, there is a method in which a sensor is moved at the same time as the welding torch to detect the positional deviation of the welding line, and the position of the welding torch is made to follow the welding line, and a method in which the welding torch is oscillated in a direction perpendicular to the welding line. , a wide range of welding methods are used.

However, in the copying device, the welding torch position adjustment mechanism and control device are complicated and expensive, and the Oscillator I method has a limited tolerance for positional deviation, making it difficult to employ in mass-produced welding devices.

In general, for objects to be welded that are intended for mass production, the position of the weld line of the object varies from production lot to production lot, but the variation within the same lot is small and often has little effect on the welding result.

Therefore, there is no need to install a particularly expensive copying device.
For simple shapes (straight lines or circles), a single sensor is used, and for complex curves, multiple sensors are used to ensure that the position of the weld line is within an acceptable range relative to the defined trajectory of the welding torch before welding begins. By confirming whether or not the welding is present, a satisfactory welding result can be obtained without using complicated and expensive equipment as in the conventional method described above.

However, in conventional welding line confirmation devices, sensors and amplifiers are connected individually, and when confirming the position of a welding line using multiple sensors, the same number of amplifiers as sensors are required, making it relatively expensive.

The present invention provides a required number of sensors according to the welding line, and outputs the outputs of all sensors through a discrimination circuit having a switching circuit.
If there is a signal indicating a welding line position failure when inputting the signal to two amplifiers, the welding object will be treated as a welding line failure and an alarm or a signal to stop the welding machine will be output. The purpose of the present invention is to provide an economical weld line confirmation device.

FIG. 1 is an explanatory diagram when the apparatus of the present invention is used for butt circumferential welding of pipes.

In the figure, reference numeral 1 indicates a welding line position detection sensor, which in this case is provided at four locations: upper, lower, left, and right.

It is assumed that the detection sensor 1 outputs a low level signal (L signal) when the position of the weld line is good, and outputs a high level signal (H signal) when it is defective.

2 and 2' are pipes to be welded, and are butted together at a weld line 3.

4 is a discrimination circuit which receives each output signal of the detection sensor 1 as input;
5 is an amplifier, and 6 is an output relay.

Of course, if the output of the discrimination circuit 4 can be used as is, the amplifier 5 and output relay 6 can be omitted.

Prior to welding, the detection sensors 1 are brought close to the surface of the workpiece 2 by a moving mechanism (not shown).

After the detection sensor 1 approaches the object to be welded 2, the respective outputs are discriminated by the discrimination circuit 4, and it is determined whether any one of them is an H signal (a signal for poor position of the welding line). I (signal), is amplified by amplifier 5, and excites output relay 6 to operate it.

The contacts of the output relay 6 are used to display a defective welding line or to stop the welding machine.

When the output characteristics of the detection sensor 1 are reversed, that is, an H signal due to a good welding line position and an L signal due to a poor welding line position,
An AND circuit may be used as the discrimination circuit 4, and an inverting amplifier may be used as the amplifier 5.

FIG. 2 is a schematic connection diagram showing a specific embodiment of the discrimination circuit 4. In FIG.

In the same figure, 401 is a stepping relay that performs stepping operation using pulses output from the pulse oscillator 7;
1C is a counting coil thereof, 401a is a contact for a stepping operation, and 401R is a noset coil for returning the contact 401a to its initial position.

Further, 402 is an amplifier, and CR is an output relay.

Furthermore, 8 indicates a reset pushbutton switch, 1a to 1a.
1X indicates a welding line detection sensor.

After the detection sensors 1a to 1X are set at predetermined positions, the stepping relay 401 is driven by the output signal of the pulse oscillator 7, and the outputs are sequentially connected to the amplifier 402 starting from the detection sensor 1a.

If any one of the detection sensors 1a to 1X outputs a welding defect signal (for example, a high level signal) during this process, the amplifier 402 outputs a high level signal when the contact 401a comes to that location. output, and excites the output relay CR to operate it.

As a result, the normally open contact CRa2 of the output J-ray CR closes to issue an alarm, and the coil of the output relay CR closes the contact CRa.

It is directly connected to the power supply +E to hold itself and memorize that the position of the weld line is defective.

Note that instead of using the mechanical stepping relay shown in the figure as the stepping relay 401, it is also possible to use an IC or the like to make it contactless.

As an example of a sensor used in the present invention, FIG. 3 shows an example of a sensor that magnetically detects the position of a weld line.

In FIG. 3, 101 is an excitation coil, and the iron core 10
2, and an alternating current is passed through it by a power source S.

W is an object to be welded, and is a butt portion W. shall be welded.

103 and 103' are differentially interconnected detection coils, which are driven by the alternating magnetic current generated by the excitation coil 101.
Voltage e103. shown in FIG. e103' is induced.

Since the two detection coils are differentially connected as outputs of the sensor, the center of the sensor is the abutting portion W.

When it matches, the differential voltage (e103-e103'
) becomes hoho zero, and W.

When the weld line is slightly removed from the weld line, it increases rapidly, clearly indicating that the weld line has been moved away from the weld line.

FIG. 4 shows the change in the output value at this time.

In the figure, the horizontal axis represents the sensor and the welding line W.

The vertical axis is the output voltage.

As can be seen from the figure, the portion where the output voltage is approximately zero is determined to be the weld line.

Sensors for detecting welding lines used in this invention include those using non-contact magnetic properties as shown in Figure 3, those using a light source and photoelectric element, and those using ultrasonic waves. , or any of the other six types of non-contact type sensors, or in cases such as when the weld line has a groove or fillet welding, a sensor of a type in which a contactor is brought into direct contact with the weld line may be used.

According to the device of the present invention, as shown in FIG. Since it is possible to check whether the position of the welding line of the object to be welded is good or not, the device is not only simple and inexpensive to manufacture, but also reduces the number of parts used and almost eliminates damage.

Furthermore, it does not compare the values of the output signals of individual sensors, but only determines whether a high-level output is a low-level output.
It is easy to adjust the levels without having to match them exactly.
Moreover, since there is no need for readjustment even during long-term use, a highly reliable device can be obtained over a long period of time.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of the device of the present invention, Fig. 2 is a connection diagram showing an example of a discrimination circuit, Fig. 3 is a diagram showing an example of a detection sensor, and Fig. 4 is an illustration of the sensor of Fig. 3. This is a diagram showing the output of each part. 1... Detection sensor, 2, 2'... Work to be welded, 3...
- Welding line, 4...discrimination circuit.

Claims (1)

[Scope of utility model registration request] A step circuit that has a plurality of sensors that detect the position of the weld line of the workpiece corresponding to welding 1 to 1, and has input terminals at least as many as the number of sensors, and sequentially switches the human input signal of each input terminal. and a memory circuit that stores the signal and outputs an alarm or a welding machine stop signal when even one of the output signals of the sensors switched and supplied by the step circuit is a signal indicating a positional defect in the welding line. A welding line confirmation device equipped with a discrimination circuit.