Patent attributes
A positioning structure for a pivotal shaft comprises a positioning device for use in the pivotal shaft. The positioning structure is located between a base and a lid of an electronic product, wherein an inner sleeve is pivotally connected to an outer sleeve through an elastic device. The positioning device is composed of a rotation ring and a ring cover. A toothed ring is mounted on each side of the rotation ring, and a limit block is protrudent from the edge of the rotation ring. The ring cover has a locking trench, and the toothed rings are inserted into the locking trench. The elastic device is pre-rotated. When the push-button switch is separated from the buttonhole by pressing, the lid is lifted up by the anti-twist force and the lower edge of the lid is exactly stopped by the limit block for positioning the lid to a predetermined angle automatically.
