US 4,249,062 A · Apparatus and method for sensing welding point in automatic welding apparatus

Abstract

An automatic welding apparatus comprises a welding torch including an electrode and a fixture for fixing a workpiece, and a relative positional relation of the welding torch and the workpiece fixture is controlled such that the electrode of the welding torch is moved to trace the welding line of the workpiece, whereby automatic welding is achieved. The automatic welding apparatus further comprises a switch for selectively connecting the electrode of the welding torch to a welding power supply or a detecting power supply, and a sensor for sensing a current or a voltage between the electrode and the workpiece when the electrode is switched to the detecting power supply, whereby the relative positional relation between the welding torch and the workpiece is detected in response to the output of the sensor, and thus a welding point or a welding line is sensed. In the case where the automatic welding apparatus is a wire extension type, adapted to successively feed the electrode in accordance with the progress of welding, a collet chuck for clamping the electrode to the welding torch is provided for fixing the length of the electrode from the welding torch on the occasion of the sensing mode.

Claims81

Dependent claims

An automatic welding apparatus for performing welding operations between a welding torch having a tip end and including an electrode, and a workpiece having a welding line, said workpiece being fixed to a workpiece fixture, said welding operation being performed in accordance with a desired relative positional relation between said welding torch and said workpiece fixture, said apparatus comprising:

present positional information generating means operatively connected to said welding torch and said workpiece fixture for generating present positional information representative of the present positions of said welding torch and said workpiece fixture,
control means including storage means for storing command positional information concerning the desired relative positional relation between said welding torch and said workpiece fixture as programmed in advance, said control means being responsive to said command positional information and said present positional information for controlling the relative positional relation between said welding torch and said workpiece fixture to said desired relative positional relation for automatically welding said welding line of said workpiece by means of said electrode of said welding torch,
voltage supply means coupled to said electrode of said welding torch for supplying a voltage to said electrode of said welding torch, said voltage supply means having a sensing mode and a welding mode,
mode selecting means operatively coupled to said voltage supply means for selectively changing the mode of said voltage supply means to a selected one of said sensing mode and said welding mode,
means operatively coupled to said electrode of said welding torch for detecting an electric current conduction state in said electrode in said sensing mode, and
means responsive to the output of said electric current conduction state detecting means for supplying said present positional information of said present positional information generating means to said control means.

3 more elements

A method for sensing a welding point in an automatic welding apparatus for performing welding operations between an electrode of a welding torch and a workpiece having a welding line and affixed to a workpiece fixture, the automatic welding apparatus performing the welding operation based on a welding point evaluated responsive to the sensed welding point, the automatic welding apparatus comprising voltage supply means coupled to the electrode of the welding torch for supplying a voltage to the electrode of the welding torch, the voltage supply means having a sensing mode and a welding mode, and mode selecting means operatively coupled to the voltage supply means for selectively changing the mode of the voltage supply means to a selected one of the sensing mode and the welding mode, the sensing method comprising, when the sensing mode is selected by the mode selecting means, the steps of:

controlling the positions of the welding torch and the workpiece fixture such that the electrode is brought in proximity of the welding line,
detecting whether an electrical conduction state has occurred between the electrode of the welding torch and the workpiece,
generating information representative of the position of at least one of the welding torch and the workpiece fixture at the time of detection of the electrical conduction state, and
evaluating the welding point based on the generated information.

1 more element

An apparatus for sensing a welding point in an automatic welding apparatus for performing welding operations between an electrode included in a welding torch and a workpiece having a welding line and fixed to a workpiece fixture, said welding operation being performed based on a welding point evaluated in response to the output of said sensing apparatus, said sensing apparatus comprising:

voltage supply means coupled to said electrode of said welding torch for supplying a voltage to said electrode of said welding torch, said voltage supply means having a sensing mode and a welding mode,
mode selecting means operatively coupled to said voltage supply means for selectively changing the mode of said voltage supply means to a selected one of said sensing mode and said welding mode,
detecting means operatively coupled to said electrode of said welding torch for detecting the occurrence of electrical conduction between said electrode and said workpiece in said sensing mode,
positional information generating means operatively coupled to at least one of said welding torch and said workpiece fixture for generating positional information representative of the position of at least one of said welding torch and said workpiece fixture based on the output of said detecting means in said sensing mode, and
control means for controlling the positions of said welding torch and said workpiece fixture in said sensing mode for bringing said electrode into proximity with respect to said welding line, said control means being responsive to said positional information from said positional information generating means for evaluating information concerning said welding point.

2 more elements

Dependencies are inferred from the claim text.

Apparatus and method for sensing welding point in automatic welding apparatus

Life of this patent

Apparatus and method for sensing welding point in automatic welding apparatus

Life of this patent

Abstract

Claims81