US Patent 10966490 Female button and combination of female button and male button

A female button is in an unlocked state when a rotator takes a first position and is in a locked state when the rotator takes a second position, insertion and removal of a post of a male button being allowed in the unlocked state, and insertion and removal of the post of the male button being hindered in the locked state. Arresting part or elastic member is provided with a projection which, when the rotator rotates toward the second position, displaces the arresting part toward the rotational axis before the rotator reaches the second position and, if the displacement of the arresting part toward the rotational axis is obstructed by the post, rotational resistance of the rotator is increased.