Plug member and low-temperature storage

Abstract

A plug member, which is to be used for a low-temperature storage including: a heat-insulating door to close an opening face of a heat-insulating housing; a cooling device; and a through-hole passing through a heat-insulating wall in the housing and having an internal thread on an inner periphery thereof, and which closes an opening portion of the through-hole on an outer side of the storage, includes: an external thread to be threadedly engaged with the internal thread; and a flange member to abut onto a face having the opening portion and close the portion, by threaded engagement between the external and internal threads, the external thread having a cut, which opens a part of the opening portion, formed in a portion of an outer periphery thereof, in a state where the flange member does not abut on the face, while the external thread is threadedly engaged with the internal thread.

1 . A plug member to be used for a low-temperature storage including: a heat-insulating housing including an opening face; a heat-insulating door configured to open or close the opening face; a cooling device configured to cool an article stored inside the heat-insulating housing; and a through-hole passing through a heat-insulating wall included in the heat-insulating housing from an outer side of the storage to an inner side thereof and having an internal thread formed on an inner periphery thereof, the plug member configured to open or close an opening portion of the through-hole on the outer side of the storage, the plug member comprising:
 an external thread configured to be threadedly engaged with the internal thread; and   a flange member configured to abut onto a face having the opening portion formed therein and close the opening portion, by threaded engagement between the external thread and the internal thread,   the external thread having a cut formed in a portion of an outer periphery thereof, the cut configured to open a part of the opening portion in a state where the flange member does not abut on the face having the opening portion formed therein, while the external thread is threadedly engaged with the internal thread.   
     
     
         2 . The plug member of  claim 1 ,
 wherein the external thread is a thread having the cut formed in a portion of the outer periphery of a column member.   
     
     
         3 . The plug member of  claim 1 ,
 wherein the external thread has the cut formed over an entire length thereof in a direction of the threaded engagement.   
     
     
         4 . The plug member of  claim 2 ,
 wherein the external thread has the cut formed over an entire length thereof in a direction of the threaded engagement.   
     
     
         5 . The plug member of  claim 3 ,
 wherein the external thread includes a plurality of cuts as the cut.   
     
     
         6 . The plug member of  claim 4 ,
 wherein the external thread includes a plurality of cuts as the cut.   
     
     
         7 . A low-temperature storage comprising:
 a heat-insulating housing including an opening face;   a heat-insulating door configured to open or close the opening face;   a cooling device configured to cool an article stored inside the heat-insulating housing;   a through-hole passing through a heat-insulating wall included in the heat-insulating housing from an outer side of the storage to an inner side thereof and having an internal thread formed on an inner periphery thereof; and   a plug member including an external thread configured to be threadedly engaged with the internal thread and a flange member configured to abut onto a face by threaded engagement between the external thread and the internal thread, the face having an opening portion formed therein of the through-hole on the outer side of the storage, the plug member configured to open or close the opening portion,   the external thread having a cut formed in a portion of an outer periphery thereof, the cut configured to open a part of the opening portion in a state where the flange member does not abut on the face having the opening portion formed therein, while the external thread is threadedly engaged with the internal thread.   
     
     
         8 . The low-temperature storage of  claim 7 ,
 wherein the through-hole is formed on the heat-insulating wall on a side surface of the heat-insulating housing.