| 摘要 |
PURPOSE:To make fitting and demounting of a vent plug into and from a fitting hole of a metal mold easier, by making a slit along with the radial direction at the part of larger diameter which has a little larger outer diameter than the inner diameter of the plug-fitting hole of the metal mold. CONSTITUTION:A part of larger diameter 1 to be located at the end part of an inner surface of a metal mold and a part of smaller diameter 3 adjacent to the part of larger diameter 1 via a taper part 2 are prepared. The outer diameter D1 of the part of larger diameter 1 is a little larger than the inner diameter D2 of a plug-fitting hole 5 of a metal mold 4 and the outer diameter D3 of the part of smaller diameter 3 has such a dimension that a space 6 can be made between the outer surface 3a and the inner wall 5a of the plug-fitting hole 5. A radial slit 7 is setup at the part of larger diameter and the slit 7 extends along to the axial direction from the inside end 1a of the metal mold to the part 3b of the part of smaller diameter penetrating the part of larger diameter 1, the radial slit 7 being thereby connected with the space 6 which exists at the outer surface of the part of smaller diameter 3 to constitute an air-evacuating path. The outer diameter of the part of larger diameter 1 decreases when the part of larger diameter 1 is driven and fitted into the plug-fiting hole 5 and the fitting driving and into the plug-fitting hole can be thereby easily performed. |
