JPH05200561A - Device for confirming weld bolt - Google Patents

Abstract

PURPOSE:To eliminate a dog adjustment by providing on the upper electrode an air passage that is opened at the lower end of the electrode, flowing air, detecting changes in air pressure and confirming the presence of a weld bolt. CONSTITUTION:The weld bolt 2 is welded onto a metal plate 1. The upper electrode 4 is lowered, and the metal plate 1 and the bolt 2 are held between the upper electrode 4 and the lower electrode 3 and pressurized. An air pressure is supplied from an air inlet 9 to the air passage 7, and the air pressure is detected by a pressure switch 10. If the bolt 2 is present, the air is blocked by the head part of the bolt 2, and the pressure is raised. If the bolt 2 is not present, the pressure is not raised. Thus, the presence of the bolt 2 is discriminated. A frequent adjustment is no longer required. Also, by flowing air in the state where the bolt 2 is not present, spatters accumulated in holes 5, 6 are easily cleaned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weld bolt confirmation device in an electric resistance welding machine.

[0002]

2. Description of the Related Art In order to resistance weld a weld bolt 2 to a metal plate 1, the metal plate 1 is placed on a lower electrode 3, a screw portion of the weld bolt 2 is inserted into a hole of the metal plate 1, and the weld bolt 2 is inserted from above. The upper electrode 4 is pressed against the head of the device to pass an electric current.

The lower electrode 3 has a hole 5 into which the threaded portion of the weld bolt 2 is inserted and a spatter escape hole 6 communicating with the hole 5. Then, in order to confirm the existence of the weld bolt 2, the limit switch 9 is engaged with the dog 8 fixed to the shaft 7 which moves up and down together with the upper electrode 4, and the stroke of the upper electrode with and without the weld bolt 2 is engaged. It was detected by the limit switch using the difference (only for the thickness of the bolt head).

[0004]

SUMMARY OF THE INVENTION In the above conventional technique,
Since the stroke of the upper electrode changes due to the consumption of the upper electrode, it is necessary to adjust the dog frequently, or spatters are accumulated in the holes 5 and 6 of the lower electrode, which necessitates regular cleaning. was there.

Therefore, an object of the present invention is to provide a weld bolt confirmation device which does not require such a trouble.

[0006]

In order to achieve the above-mentioned object, the weld bolt confirmation apparatus of the present invention comprises an upper electrode (4).
Air passage (7) penetrating inside and opening at the lower end of the upper electrode
A pressure switch (9) for detecting a change in pressure is provided in the air circuit, and the presence or absence of the weld bolt is confirmed by the signal of the pressure switch.

[0007]

When the air is passed through the air passage (7) provided in the upper electrode (4), the holes (5) and (6) of the lower electrode are emptied from the air passage (7) when the weld bolt is not missing. Although the air flows to, the air does not flow when the weld bolt is provided because the lower end opening of the air passage (7) is closed by the head of the weld bolt.

Since the flow of air changes depending on the presence or absence of the weld bolt, the signal of the pressure switch inserted in the air circuit changes depending on the presence or absence of the weld bolt.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 1 is a metal plate, 2 is a weld bolt to be projection welded to the metal plate 1, 3 is a lower electrode having a hole 5 and a spatter escape hole 6, and 4 is an upper electrode which is opened at the lower end thereof. The air passage 7 that runs through it.

Air pressure is supplied to the upper opening of the air passage 7 through a rubber tube 8. Reference numeral 9 is an air supply port, and 10 is a pressure switch provided in these air circuits. The electric signal of the pressure switch 10 is input to the control device 11.

When the electrode 4 is lowered and pressurized, air is flowed from the air supply port 9 through the rubber tube 8 to the air passage 7. When the weld bolt 2 is present, air is stopped by the head of the bolt, so that the pressure of the pressure switch 10 rises, the switch is closed, and electrical O. K. The signal is given to the controller 11.

When the weld bolt 2 is not missing,
The air flows through the holes 5 and 6 of the lower electrode 3 from the lower end opening of the air passage 7.
The pressure of the pressure switch does not rise because it escapes to the electric N.V. The G signal is given to the control device 11.

Since the presence / absence of the weld bolt 2 can be detected in this manner, it is suitable to be used to prevent defective weld bolts 2.

[0014]

Since the weld bolt confirmation device of the present invention is constructed as described above, frequent adjustments are unnecessary, and the holes 5 and 5 can be formed by flowing air without bolts.
The spatter accumulated in 6 can be easily cleaned.

[Brief description of drawings]

FIG. 1 is a front view of a main part of an embodiment of the present invention.

FIG. 2 is a front view around electrodes of a conventional technique.

FIG. 3 is a schematic diagram of a prior art limit switch actuation mechanism.

[Explanation of symbols]

 3 Lower electrode 4 Upper electrode 5 Hole 6 Sputter escape hole 7 Air passage 9 Pressure switch

Claims (1)

[Claims] 1. An air passage (7) which penetrates through the upper electrode (4) and opens at the lower end of the upper electrode is provided, and air is caused to flow through the air passage (7), and a pressure change is caused in the air circuit. A weld bolt confirmation device in a resistance welding machine, in which a pressure switch (9) for detection is provided and the presence or absence of a weld bolt is confirmed by a signal of the pressure switch.