Injection mold for molding information recording discs

Abstract

An improved injection mold for molding an information recording disc is provided. It includes a holder frame fitted to a mold fitting plate, a mirror platen member for a stamper held in the holder frame, a tubular inner periphery holder fitted into a central hole bored through the mirror platen member and provided with a threaded portion on the outer periphery thereof near the leading end, a pilot bush and an anchor nut for holding the inner periphery holder, and is characterized in that said inner periphery holder is provided with a screw section having a plurality of intermittently disposed threaded portions projecting forwardly from the leading end thereof and said pilot bush is provided at the leading end thereof with a locking flange having at areas close to the center thereof through holes for allowing respective threaded portions to run therethrough and project further while the mold fitting plate is provided in the inside with an rotatable anchor nut so that the inner periphery holder can be firmly secured to the mold fitting plate through screwed engagement of the anchor nut and the threaded section can be made to abut the corresponding surface of the locking flange.