| 摘要 |
PURPOSE:To make fitting and demounting of a vent plug into and from plug fitting hole easier, by providing a cylindrical plug main body having a little larger outer diameter than the inner diameter of a plug-fitting hole of a metal mold and setting a cross slit connected with the vent hole and extended to the other end of the plug main body. CONSTITUTION:A cylindrical plug main body 1 having a little larger outer diameter D1 than the inner diameter of a plug-fitting hole of a metal mold is provided. A air-evacuating hole 2 of a specified length L2 from an end 1a of this plug main body, namely the end surface to be located at the inside of the metal mold, extended to the axial direction, and a cross slit 3 connected to this vent hole 2 and extended to the other end 1b of the plug main body along to the axial direction of the plug are set up. A spring effect is produced in the vent plug itself by setting the cross radial slit 3 and thereby the vent plug is easily driven and fitted into the plug fitting hole 6 as the outer diameter of the vent plug decreases when it is fitted into the plug fitting hole having smaller diameter D2 than the outer diameter D1 of the plug main body 1. The vent plug can thereby surely adhere and be fixed to the inner wall of the plug fitting hole 6 by the spring effect of the vent plug itself. |
