attached to upper up down extension arm assembly 4 at its lower end upon up down motion when a user is entering or exiting the vehicle its interlocking design shown in the right side detail callout of fig1 c provides both torsional rigidity for upper up down extension arm assembly 4 as up down drive assembly 7 forces it to travel or down the length of its contact surface with lower up down extension arm assembly 3 the design of seat support assembly 5 affords a slot designed to receive slide tray assembly 6 allowing it to travel fore and aft relative to the longitudinal axis of the vehicle when the seat is in the fully up and stowed position as shown in fig1 a 1b and 1c and outboard and inboard relative to the vehicle 39 s longitudinal axis when the seat is rotated outward as it would be when the user is boarding the seat or about to transfer off the seat when exiting the vehicle up down drive assembly 7 is attached at the upper end to lower up down extension arm assembly 3 and at the lower end to upper up down extension arm assembly 4 although fig1 a 1b and 1 c depict the motor at the lower end of the upper up down extension arm assembly 4 the motor may be located wherever convenient for the designer or user and is not limited to the shown configuration in the slide tray version of the apparatus 100 slide tray drive mechanism 10 is connected at one end to slide tray assembly retainer plate 11 and at the other to slide tray assembly 6 slide tray assembly retainer plate 11 incorporates a hole which allows.