Patent ID: 7027845

Claim:
A hinge of the mobile phone device for rotatably connecting a main body section with a cover body section, comprising: a tubular member having a bottom formed on one end; a catch slidably fitted into the other end of the tubular member in an axial direction, and including engagement projected parts each having a convex surface with a specified radius of curvature formed thereon, the engagement projected parts provided at positions symmetric about a center of a surface portion perpendicular to the axial direction, respectively; energizing means, contained in the tubular member, for energizing the catch; and a disk having engagement recessed parts, which are provided in regions opposed to the respective engagement projected parts of the catch, and which are engaged with the respective engagement projected parts, and rotatably connected with the catch, each of the engagement recessed parts having concave surfaces with a radius of curvature larger than the radius of curvature of the engagement projected parts having concave surfaces with a radius of curvature larger than the radius of curvature of the engagement projected parts formed thereon, wherein at a closed position of the cover body section and at a position at which expansion of the cover body section is restricted to 180 degrees or less, an engagement state in which the engagement projected parts are engaged with the engagement recessed parts, respectively, is maintained to fix the cover body section by an energizing force of the energizing member, and the engagement state is released by opening and closing operations of the cover body section against the energizing force.