Patent ID: 7086698

Claim:
A seat device in which an upper arm can be turned in forward and backward directions around a lower arm, comprising: an element of a contact portion having a circumferential surface formed in an end portion of said upper arm and a step portion being formed as a contact portion in an end of said circumferential surface; a base bracket fixed to said lower arm and having a long hole; a first link member being pivotally supported by a first pin of said base bracket and having a roller capable of sliding freely on said circumferential surface; a second link member one end of which is pivotally supported by said first link member by utilizing a second pin and another end of which is linked to said long hole by utilizing a third pin being inserted therein; and said third pin of said second link member can be engaged in a shallow concave portion provided in an end portion of said long hole and a position of said second link member is maintained.