Referring to FIG. 23, the plate 221 of the rotating body 220 may be disposed parallel to the vertical direction. Because the elastic force or the restoring force of the elastic member 230S is applied to the fourth part 222d of the rotating body 220, the rotating body 220 may be maintained in the current vertical state by virtue of equilibrium of force.

Referring to FIG. 24, the rotating body 220 may be inclined counterclockwise to a first angle θ1 with respect to the vertical line VL, which extends vertically through the center O of the rod 230, by the force applied by a user. Here, the other end 230Sb of the elastic member 230S may be bent toward the sleeve 231 (see FIG. 22). The elastic deformation of the elastic member 230S may be halted when the stopper 210e is engaged with the front end of the engagement recess 222e. Consequently, the rotating body 220 may be maintained in the current state, which is inclined downwards. In this state, a user is able to easily rotate the rotating body 220 to the non-inclined state from the downwardly inclined state by virtue of the elastic force or the restoring force of the elastic member 230S.