Abstract: A swinging apparatus such as a child's swinging play seat is driven by an extension spring linked between the suspension arm of the swing and a gear wheel which is coupled to a motor-driven drive shaft through meshed gears. In preferred arrangements, two gear wheels are used, arranged in coplanar configuration for reciprocal rotation in opposite directions, each driving an extension spring in alternating manner to swing the apparatus back and forth. In certain embodiments, pivot links are included to permit the extension springs to float when either the motorized drive shaft or the swing itself are stopped, and in certain further embodiments, guide pins are included to hold the springs in a bowed configuration. The mechanism is characterized by the lack of a tendency to jolt, and by the ability to start up and shut down smoothly at any point in the rotation cycle of the drive mechanism.