Patent ID: 7811091

Claim:
A rotary terminal mechanism comprising: an outside electrode provided with a circular internal peripheral surface; an inside electrode provided with a circular external peripheral surface arranged concentrically at a fixed interval relative to the circular internal peripheral surface, the outside electrode and the inside electrode being ring-shaped electrodes; a plurality of electroconductive rings that are flexible in a radial direction thereof and inserted between the circular internal peripheral surface and the circular external peripheral surface, an outside diameter of the electroconductive rings being greater than a gap between the circular internal peripheral surface and the circular external peripheral surface; retainer spacers arranged between the electroconductive rings for maintaining a constant interval between the respective electroconductive rings, each of the retainer spacers being inserted between the respective adjacent electroconductive rings such that the retainer spacer is in contact with the electroconductive rings; a fixed-side case; and a rotation-side case provided with an inside end face coaxially disposed facing an inside end face of the fixed-side case at a set interval therefrom, the rotation-side case being supported via a bearing by the fixed-side case in a rotatable state, wherein the electroconductive rings are inserted between the circular internal peripheral surface and the circular external peripheral surface in a state that they are flexed into an ellipse, are pressed against the circular internal peripheral surface and the circular external peripheral surface by an elastic restoring force thereof, and are allowed to roll along the surfaces thereof in the flexed state, one of the outside electrode and the inside electrode is a fixed-side electrode, and the other is a rotation-side-electrode, the fixed-side electrode being attached to the inside end face of the fixed-side case, the rotation-side electrode being attached to the inside end face of the rotation-side case, and one of the fixed-side case and the rotation-side case is formed therein with an insertion aperture for inserting the electroconductive rings and the retainer spacers between the circular internal peripheral surface of the outside electrode and the circular external peripheral surface of the inside electrode, the insertion aperture being sealed by a lid member.