Patent ID: 7784640

Claim:
A lid unit for closing a container body of a portable thin plate supporting container in which a plurality of thin plates are housed, with a gasket interposed between the lid unit and the container, said lid unit having opposing inner and outer surfaces and comprising: on said outer surface, at least one simplified attaching and detaching mechanism for removably attaching the lid unit to the container body, said attaching and detaching mechanism comprising: a locking member having upper and lower opposing surfaces and slidably mounted on a planar surface of a body portion of the lid unit for linear movement between an extended position engaged within an opening in a rim of the container body to secure the lid unit to the container body and a retracted position allowing the lid unit to be removed from the container body, the locking member having a distal end disposed at the extremity of the locking member, the distal end reaching the receiving structure in a state in which the lid unit lightly contacts the container body without forcibly pressing the lid unit against the container body and guides the locking member into the receiving device, wherein the distal end is beveled to provide a surface inclined to the upper and lower surfaces, the inclined surface extending from a tip of the distal end of the locking member and extending away from the bottom surface to form a distal fitting portion on the upper surface, the inclined surface serving as a guiding portion for slidably engaging an edge of the opening in the rim of the container body as the locking member is extended, whereby the lid unit is pressed inwardly; on the outer surface, a rotary actuator which is connected to the locking member for, responsive to rotation, moving the locking member linearly between its extended and retracted positions; on the inner surface, a wafer holding unit for resiliently supporting peripheral portions of the thin plates to prevent the thin plates from contacting each other; and cam means for forcing a proximal end of the locking member downward and the distal end of the locking member upward as the locking member is extended into the opening in the rim of the container body, pressing the lid unit against the container.