Patent ID: 6541760
Filing Date: 2003-04-01
Classification: G01D

Abstract:
A rotation detecting apparatus, comprising:a first rotating body; a second rotating body serving as an input side of rotation force that rotates along with the first rotating body; light transmission paths formed on both the first rotating body and the second rotating body; and detecting means for detecting light passing through both the light transmission paths of the first rotating body and those of the second rotating body, wherein the first rotating body and the second rotating body can rotate relatively within a predetermined allowance angle range; wherein, when rotation force is inputted to the second rotating body, and the second rotating body and the first rotating body are rotating together in a rotation input direction, the light transmission paths of the first rotating body and those of the second rotating body overlap one another and light can be detected by the detecting means; and wherein, when input of the rotation force to the second rotating body is broken and the first rotating body continues to rotate by inertia force in the rotation input direction, the second rotating body rotates relative to the first rotating body in a direction opposite to the rotation direction of the first rotating body within the allowance angle range, the light transmission paths of the first rotating body and those of the second rotating body deviate in position from each other, and the light to the detecting means is cut off.