Rickey’s first forays into moving sculpture were mobiles which had no motors; they were put in motion by the currents of the air. They operated on a basic system of multiple levers with individual fulcrums on a superstructure suspended by a wire from the ceiling or a post. The wire or post served as the pendulum. With its weight carefully distributed so it moved in the way Rickey intended, a lever might be a single element [See video of Construction (1951-1952)] or multiple pieces affixed to two ends of a wire, creating a weight on one end and a counterweight on the other that held it in balance.
Rickey soon moved away from hanging mobiles. He began by experimenting with the same principles of balance and motion with the elements standing directly on posts. To increase the range of motion of these elements, Rickey began using knife edge bearings and gimbals on which the components of his pieces could stand vertically or horizontally, and move within a single plane or sometimes slightly beyond in a small circle. Color became incidental. By the late 1950s, he was insisting that the new term “kinetic sculpture,” rather than mobiles, be used to describe his work.
After knife edge bearings proved to be too sensitive and exposed for large outdoor works, Rickey began using ball bearings, encased in bearing housings, which were both more precise and secure. While on the smaller pieces, Rickey could arrest the movement of an element by adjusting the configuration of the knife edge, the larger sculptures required shock absorbers to stop where Rickey intended. Ball bearings also allowed for 360-degree movement and, by employing them in his work, Rickey could now make sculptures that were gyratory, revolving 360 degrees around a central post. [See video of Two Conical Segments Gyratory Gyratory II (1979)]