Patent ID: 7503542

Claim:
A removable marking device for a mold comprising: a substantially cylindrical fixed tube having relief characters on its upper surface, and said fixed tube adapted to be fixed to said mold; a substantially cylindrical rotatable tube having relief characters on its upper surface, and the rotatable tube rotatably inserted into said fixed tube; an indicator axle inserted into said rotatable tube; a control mechanism that allows only said indicator axle to rotate when said indicator axle rotates in one direction and that allows said indicator axle to rotate with said rotatable tube when said indicator axle rotates in the other direction; a disk-shaped base member disposed in a bottom of said rotatable tube, wherein said control mechanism comprises: a control space formed inside said rotatable tube; and a fixing portion that moves in and out radially and that is inserted in said indicator axle; wherein said control space comprises: a cylindrical space that is concentric with an axis of said rotatable tube; and a projecting space protruding radially from said cylindrical space, and said projecting space having a pair of sides extending from said cylindrical space; wherein an imaginary line is defined between two points from which said pair of sides extending from said cylindrical space; wherein the angle between one of said pair of sides and said line is different from the angle between the other of said pair of sides and said line; wherein said indicator axle is made of porous metallic material having interlinked pores so that gas flows in an upper surface of said indicator axle through the inside of said indicator axle to said projecting space and exits from a bottom surface of said marking device; and wherein said base member has a through-hole vertically extending therethrough and communicating with said projecting space.