JPS6243789B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control circuit device for an arc stud welding machine.

[Prior Art] Conventionally, when trying to arc weld a stud to a base material using an arc stud welding machine, if the base material to be welded was coated with insulating paint such as paint or rust preventive, Even if the stud is pressed against the surface of the base metal, there is no electrical current between the stud and the base metal, so a welding arc will not occur, and therefore, the paint on the base metal part that is to be welded using a file, hammer, etc. Stud welding was performed by peeling off the material and then operating the arc stud welding machine. Examples of such arc stud welding machines include those disclosed in Japanese Patent Publication No. 45-34686 and Japanese Patent Application Laid-Open No. 48-85457.

[Problems to be Solved by the Invention] By the way, when welding a relatively large number of studs using the conventional arc stud welding machine as described above, it takes considerable time and effort to remove the paint, which reduces work efficiency. There were other problems, such as a decrease in paint quality and the tendency for paint to peel off from areas other than the welded areas of the stud.

Therefore, the present invention provides a method for polishing the surface or removing the paint in advance by using a separate means, even if the base material to be welded is extremely dirty or covered with a relatively thick insulating paint. It is an object of the present invention to provide a control circuit device for an arc stud welding machine that can reliably weld a stud to a base material without the need for welding.

[Means for Solving the Problems] In order to achieve the above object, a control circuit device for an arc stud welding machine according to the present invention provides a welding welding machine that is energized in response to the operation of a trigger switch provided in a welding gun. a solenoid in the gun for pulling up the stud; a welding circuit comprising a first rectifier bridge circuit and an output terminal to which the stud and the base metal are electrically connected; a pilot arc current supply circuit comprising a second rectifier bridge circuit for supplying a pilot arc current; a phase control circuit connected to the first rectifier bridge circuit in the welding circuit; an ignition circuit that supplies an ignition signal to the gate electrode; when no current is present between the stud and the base metal;
a hammer operation control circuit comprising a third rectifier bridge circuit whose ignition is controlled by a relay device responsive to conduction or non-conduction of the pilot arc current supply circuit in order to energize the solenoid intermittently for a predetermined time; the welding circuit; and a timer circuit for setting the welding current supply time and the operation time of the hammer operation control circuit.

Further, in the apparatus according to the present invention, a temperature-sensitive switch is provided in the power transformer to ensure the safety of the apparatus, and the operation of this switch opens the power supply input side disconnector.

[Embodiment] Hereinafter, an embodiment of a control circuit device according to the present invention will be described with reference to the accompanying drawings.

In the drawing, 1 and 2 are input power terminals, 3 is a disconnector, 4 is a power transformer, 5 is a temperature-sensitive switch inserted into the power transformer 4, and 6 is two diodes 6.
a, 6b and two silicon controlled rectifiers 6c, 6
a first rectifier bridge for a welding circuit consisting of d;
7 and 8 are output terminals of the welding circuit, which are connected to the stud and the base metal, respectively. Further, 9 is a second rectifier bridge, 10 is a phase control circuit, 11 is a trigger switch provided in a welding gun (not shown),
12 is a constant voltage diode, 13 is a relay, 13
a, 13b, 13d are the normally open contacts of the relay 13, 13c is the normally closed contact of the relay 13, 14 is the silicon controlled rectifier, 15 is the dimer circuit, 16 is the relay, 16a is the normally open contact of the relay 16, 16 is the relay 16 normally closed contacts, 17 capacitors, 18
19 is a diode, 19 is a relay, 19a, 19b are normally open contacts of the relay 19, 20 is a solenoid for pulling up the stud of the welding gun, 21, 22 are diodes, 23 is a resistor, 24 is a relay device, 24a, 2
4b, 24c, 24d are normally open contacts of the relay device 24, 24e is a normally closed contact of the relay device 24, 25 is a third rectifier bridge consisting of two diodes 25a, 25b and two silicon-controlled rectifiers 25c, 25d, 26 is a diode.

In the illustrated embodiment, the welding circuit consists of a first rectifier bridge 6 and output terminals 7, 8, the gate electrodes of each of the silicon-controlled current generators 6c, 6d of the first rectifier bridge 6 being connected to a phase control circuit 10, which The phase control circuit 10 preferably consists of a transistor circuit and also includes a normally open contact 1 of a relay 16.
6a is connected to the ignition circuit of the phase control circuit 10. In the illustrated circuit, the first rectifier bridge 6
The return paths of the respective gate circuits of the silicon-controlled rectifiers 6c and 6d are omitted. A normally open contact 13a of the relay 13 is connected in parallel to the trigger switch 11, and a silicon-controlled rectifier 14 is connected in parallel to the relay 13, the gate electrode of which is connected to a conventional timer circuit 15.
The connection point between diodes D1 and D2 is connected to the connection point between diodes D1 and D2. The timer circuit 15 is a first timer element for setting the hammer operation time, which is composed of a series circuit of a capacitor C1 and a resistor R1 connected in series via the normally open contact 13b of the relay 13 and the normally closed contact 24e of the relay 24. , and a second timer element consisting of a series circuit with a capacitor C2 and a variable resistor R2 connected in series via a normally open contact 24d of the relay 24. Normally closed contact 16
b is connected.

The normally closed contact 13c of the relay 13, the relay 16, and the capacitor 17 are connected in parallel, and the normally open contact 24 of the relay device 24 is connected to the connection point of these three elements.
a and the normally open contact 13d of the relay 13 are connected in series. One end of a parallel circuit consisting of a diode 18 and a relay 19 is connected to the connection point between the normally open contacts 24a and 13d, and the other end of this parallel circuit is connected to the positive terminal of the third rectifier bridge 25 via a diode 26. It is connected.

The output terminal of the second rectifier bridge 9 is a resistor 23,
Diode 22 and normally open contact 19 of relay 19
It is connected to the output terminals 7, 8 of the welding circuit via a.

The output terminal of the third rectifier bridge 25 is connected to the solenoid 20 via the diode 21 and the normally open contact 19b of the relay 19.

The operation of the apparatus of the present invention constructed in this manner will be described below.

First, the operation of the apparatus will be described in the normal case where the connection between the stud and the base metal is energized, that is, the surface of the base metal to which the stud is to be welded is extremely dirty or not covered with an insulating layer. When the shield breaker 3 is turned on and the trigger switch 11 is turned on, the relay 13 is energized and its normally open contacts 13a, 1
3b and 13d are closed, and the normally closed contact 13c is opened. As a result, the first timer element for setting the hammer operating time in the timer circuit 15 is activated and the relay 19 is energized via the positive terminal of the third rectifier bridge 25, the diode 26 and the closed contact 13d of the relay 13; It is held in an excited state by a bootstrap diode 18.
Then, the contacts 19a and 19b are closed. As a result, a circuit passes from the positive terminal of the rectifier bridge 25 to the solenoid 20, the diode 21, and the relay contact 19b, and the solenoid 20 is energized, pulling the stud loaded in the welding gun away from the base metal against the force of the spring. let At the same time, resistor 23,
A pilot current flows between the base metal and the stud, which are connected to the output terminals 7 and 8 of the welding circuit via the diode 22 and the relay contact 19a.

The voltage drop due to the pilot current flowing through resistor 23 energizes relay device 24 and closes its normally open contact 24a, so that relay 16 is energized after a short time delay provided by capacitor 17. . As a result, contact 16a of relay 16
is closed and the phase control circuit 10 is fired by the output of the second rectifier bridge 9. Therefore, the silicon-controlled rectifier 6c of the rectifier bridge 6 of the welding circuit,
An ignition signal is applied to the gate electrode 6d, so that via this rectifier bridge 6 the welding current flows between the stud connected to the output terminals 7, 8 and the workpiece. In addition, the normally closed contact 2 in the first timer element of the timer circuit 15 is activated by energizing the relay device 24.
4e opens, thereby stopping the first timer element.

On the other hand, the second timer element of the timer circuit 15 is
The energization of the relay device 24 closes the normally open contact 24d, and the energization of the relay 16 causes the normally closed contact 16b to open, thereby providing an ignition signal to the gate electrode of the silicon-controlled rectifier 14 after a predetermined time. Feed and fire. As a result, the relay 13 is short-circuited and cut off, and the current is cut off, so that the stud is pushed into the molten base metal, completing one cycle of welding.

Next, a case will be described in which, for example, the surface of the base material is covered with an insulating layer and there is no electrical current between the stud and the base material.

As in the previous case, when the circuit breaker 3 is turned on and the trigger switch 11 is pulled, the relays 13 and 19 are energized, their normally open contacts are closed, and their normally closed contacts are opened. , the stud and the base metal are disconnected, so the resistor 23, diode 22,
No pilot arc current flows through contact 19a, so relay device 24 is not energized. Therefore, the silicon-controlled rectifiers 25c, 25d of the third rectifier bridge 25 are not fired, and this bridge acts as a half-wave rectifier circuit of the diodes 25a, 25b, so that the solenoid 20 is supplied with a half-wave DC voltage. This solenoid 20 is energized intermittently. In this case, the solenoid 20 remains energized intermittently during the hammer cycle set by the first timer element of the timer circuit 15. The stud thus has a hammering effect on the base material. If a conductive condition occurs between the stud and the workpiece during this hammer action, a pilot arc current will flow as in the case described above, which will energize relay 16 and relay device 24, conduct welding current, and set the timer. A second timer element of the circuit is activated to weld the stud to the base metal after a predetermined period of time. In this case, if the hammer cycle set by the first timer element of the timer circuit 15 ends before continuity is established between the stud and the base metal, the silicon controlled rectifier 14 fires and the relay 1
3 is then cut off and the device stops operating. Therefore, the welding operation can be continued by pulling the trigger switch 11 again. If the welding gun trigger switch is pulled before the tip of the stud is not in contact with the base metal surface, the hammering circuit will be activated and no welding will occur. Also, if you repeatedly turn on the trigger switch in a short period of time, the disconnector 3 will work.
The device is de-energized.

[Effects of the Invention] As explained above, the device according to the present invention is equipped with a hammering circuit that intermittently activates a solenoid that lifts the stud from the base material, so it is possible to prevent the surface of the base material from becoming extremely dirty. Even if the surface is coated with paint and an insulating layer is formed, reliable welding can be performed without the need to remove the insulating layer using special tools. Work efficiency is much better than conventional equipment, and a temperature-sensitive switch is inserted into the power transformer, which prevents damage to the power supply itself and ensures safe and reliable operation. .

[Brief explanation of the drawing]

The drawing is a block circuit diagram showing an embodiment of the device according to the invention. In the figure, 6: first rectifier bridge, 7, 8: output terminal of welding circuit, 9: second rectifier bridge, 1
0: Phase control circuit, 11: Trigger switch, 1
3, 16, 19, 24: Relay, 15: Timer circuit, 20: Solenoid, 25: Third rectifier bridge.

Claims (1)

[Claims] 1 a solenoid 20 for pulling up the stud in the welding gun that is energized in response to the operation of a trigger switch 11 provided in the welding gun; a first rectifier bridge circuit 6 and an output terminal to which the stud and the base metal are electrically connected; a pilot arc current supply comprising a second rectifier bridge circuit 9 connected to the output terminals 7, 8 of said welding circuit and supplying a pilot arc current between said output terminals 7, 8; circuit; a phase control circuit 1 connected to the first rectifier bridge circuit 6 in the welding circuit;
0 and supplies a firing signal to the gate electrode of each rectifier of the first rectifier bridge circuit 6;
When there is no energization between the stud and the base metal, the solenoid 20 is energized intermittently for a predetermined period of time, and the ignition is controlled by a relay device 24 that responds to conduction or non-conduction of the pilot arc current supply circuit. an arc stud welding machine comprising: a hammer operation control circuit comprising a third rectifier bridge circuit 25; and a timer circuit 15 for setting the welding current supply time of the welding circuit and the operation time of the hammer operation control circuit. control circuit device.