US Patent 9105413 Portable apparatus and portable timepiece

A pushbutton of a portable apparatus is locked against inward axial movement by engagement with a locking member when the locking member is unthreaded a distance A from the apparatus body and brought into abutment with a fixed stopper member. The pushbutton is released from its locked state when the locking member is threaded into the apparatus body and brought out of abutment with the stopper member and into abutment with the apparatus body. In its unlocked state, a head portion of the pushbutton is axially spaced a distance B from an opposedly facing portion of the locking member, wherein A≦B.