A motion conversion mechanism is described. The motion conversion mechanism includes a first member and an a second member. The firs member is configured to be arranged relative to the child containment structure to undergo motion in a first angular direction and in a second angular direction opposite to the first angular direction. The second member includes a rotation device that is rotatable about a rotation axis. The first and second members configured in combination to convert motion about the angular motion axis to motion of the rotation device about the rotation axis when the first member moves in at least one of the first angular direction and in the second angular direction.