Abstract: A no-indentation welding monitoring device may include a pressing force measuring device for measuring a pressing force for pressing a welding target of a welding tip of a welding gun, a voltage measuring device for measuring a voltage applied to the welding tip of the welding gun, and a monitor device for digitizing a welding quality by use of the pressing force and the voltage transmitted from the pressing force measuring device and the voltage measuring device.

Abstract: A tip changer for a spot welding machine includes a first rotation body that has an opening capable of accommodating a welding tip and is capable of rotating around the opening; a second rotation body that is disposed concentrically with the first rotation body and is rotated relative to the first rotation body; and a plurality of nail pieces that are disposed at equal angular intervals along an imaginary circle of the rotation bodies, are swingably connected to the first rotation body by a first connection mechanism, are swingably connected to the second rotation body by a second connection mechanism on a more radially inner side of the second rotation body than the first connection mechanism, and include contact portions on a more radially inner side of the second rotation body than a second connection mechanism.

Abstract: A no-indentation welding monitoring device may include a pressing force measuring device for measuring a pressing force for pressing a welding target of a welding tip of a welding gun, a voltage measuring device for measuring a voltage applied to the welding tip of the welding gun, and a monitor device for digitizing a welding quality by use of the pressing force and the voltage transmitted from the pressing force measuring device and the voltage measuring device.