| 摘要 |
PURPOSE:To make improvements in the positioning accuracy of an electrode holder as well as to make a large-sized, heavy electrode usable, by setting the form of the electrode holder down to a trapezoid in its section as well as setting the short side face down to the under surface, while constituting it so as to set up the electrode on this surface. CONSTITUTION:In this electrode holder 3, the under surface making up a short side of its sectional trapezoid is an electrode setting surface 5. And, an electrode clamp device 12 locked to a spindle 1 is provided with a concave guide 13 for setting the holder 3. In addition, this device 12 is formed with a pressing block 15 of a separate body so as to cause one concave part 13 to shift in a direction of right-angled with the axial direction of an electrode and to make it possible to engage or disengage to or from the device 12, Furthermore, this block 15 is supported by the device 12 body by means of a fulcrum shaft 16 interposing a pressure spring 17 whereby its retractable motion is smoothly performed. In this connection, a stopper 27 regulates an admission direction of the holder 3. Thus, a large-sized, heavy electrode is made to be usable. |
