A gear mechanism having a shuttle gear adjacent both an auxiliary gear and an action gear and a cam plate, having a shuttle lock adjacent the shuttle gear and including a cam follower riding back and forth along a first cam pathway with an action element in mechanical communication with the action gear. A motor operates the shuttle gear with rotation of the motor in a first direction rotating the shuttle gear into engagement with the auxiliary gear, activating the shuttle lock to maintain the engagement throughout a predetermined rotational range of the cam plate and rotating the cam plate back and forth driving controlled back and forth movement of the auxiliary elements, with rotation of the motor in a second direction rotating the cam plate beyond the predetermined range releasing the shuttle lock.