Abstract: A drive unit for a rotary decoration has a transmission gear train configured to include a damper such as a coil spring and is capable of imparting a visually elegant swing motion to the rotary decoration. A reciprocating stepping motor is capable of rotating or turning in both the forward and reverse directions to drive a rotary decoration in such a manner that the rotary decoration exhibits a reciprocative swing motion over a specified angular displacement. A memory circuit stores data for determining the drive timing of the stepping motor. A control circuit controls the stepping motor in accordance with the data stored in the memory circuit. The data represents the interval between drive pulses supplied to the stepping motor so as to cause the rotational speed of the rotary decoration to vary according to a sine curve.

Abstract: A driving device has a stepping motor for reciprocatively rotationally driving a decorative rotary member. A memory circuit stores a data table on the basis on which the operation timing of the stepping motor is determined. A control circuit controls the application of actuation pulses to the stepping motor on the basis of the data stored in the memory circuit. The data table is made up of numeric values representative of the inter-pulse spacing of the actuation pulses, the inter-pulse spacing being selected such that the rotational speed of the rotary decorative member varies in conformity with a sine curve or the rotation angle of the decorative rotary member varies in conformity with a secant function.