Patent attributes
A seat apparatus for a vehicle includes a seat cushion, a lower arm, a seat back, an upper arm, an intermediate arm, a reclining mechanism, and a lock mechanism. The lock mechanism includes a first plate member, a second plate member, and a pawl gear. The first plate member is fixed to one of the upper arm and the intermediate arm to be provided therein with a plurality of internal tooth sections each of which has a plurality of teeth with different widths. The second plate member is fixed to the other one of the upper arm and the intermediate arm so as to be supported by the first plate member to rotate relative thereto. The pawl gear is supported by the second plate member and has an external tooth section each of which has a plurality of teeth with different widths for engaging with the internal tooth sections.