| 摘要 |
PURPOSE:To make it possible to detect a welded part automatically and definitely by making use of a difference in color or reflection coefficient between the welded part and base metal, by projecting light on the circumferential surface of a wheel rim while the welded wheel rim is turned once. CONSTITUTION:Wheel rim 1 is rotated by rim rotating unit 2 at a constant speed and in a constant direction. Light 4 emitted by light projector 3 strikes the circumferential wall of wheel rim 1, where it is reflected to reach photo detection part 5 of light projector 3. At this time, even after the welding of part 6 of wheel rim 1, it is darky in comparison with other wheel base metal parts, so that a scan by projecting light 4 will change the reflected light in color. The change of the reflected light like this is transferred to color-difference or reflection-coefficient difference discriminator 7, where when the change of the reflected light, i.e. welded part 6 is discriminated, a signal is immediately sent out to rim rotation controller 8, thereby stopping the drive of rim rotating unit 2. |
