Abstract: A seat structure includes a seat cushion supporting frame connected to a platform by suspension linkage permitting vertical movement of the seat relative to the platform, the platform in turn being connected to a base through means of guide track and latch means for permitting selected fore-and-aft adjustment of the platform relative to the base member. A U-shaped safety bar is disposed such that opposite vertical legs thereof extend upwardly through fore-and-aft extending openings in a horizontal plate member of the platform, the upper ends of the legs of the safety bar being fixed to the platform so that the safety bar is carried therewith during fore-and-aft adjustment of the platform.