Hinge mechanism for a foldable portable telephone

A hinge mechanism for a foldable portable telephone composed of a main housing and a foldable housing which is rotatably supported to the main housing by the hinge mechanism to rotate the foldable housing between an opened position and a closed position, comprising a pair of shaft units,

• each of the shaft units comprising:
• a first cylindrical member engaged with the main housing, the first cylindrical member having a first cylindrical hollow formed therein, and an inner side wall of the first cylindrical hollow having a plurality of positioning recesses formed in a predetermined pattern corresponding to at least the opened position;
• a second cylindrical member engaged with the foldable housing, the second cylindrical member having a second cylindrical hollow formed therein and a plurality of holes formed in a side wall thereof, wherein the second cylindrical member is rotatably fit in the first cylindrical hollow of the first cylindrical member;
• an elastic cylinder fit in the second cylindrical hollow of the second cylindrical member;
• a sphere freely fit in each of the holes of the second cylindrical member, wherein spheres fit in the holes are pinched between the elastic cylinder and the inner side wall of the first cylindrical hollow of the first cylindrical member to allow each sphere to be fit into a corresponding one of the positioning recesses;
• and
• a stopper for stopping the shaft unit moving in an axial direction of the hinge mechanism.