Four-bar linkage long reversible seat

The utility model discloses a four-bar linkage long reversible seat which comprises a backrest, armrests, a seat cushion and a safety belt, and further comprises a linkage mechanism, an automatic plug-pin mechanism and connecting bar mechanisms. The backrest and the seat cushion are connected through a seat hinge. The linkage mechanism is in connection with the backrest and the seat cushion, and the backrest and the seat cushion are installed on a side wall of a car through the linkage mechanism. The seat cushion is in connection with one end of each connecting bar mechanism, and the backrest is in connection with the other end of each connecting bar mechanism. The armrests are installed on the connecting bar mechanisms. The four-bar linkage long reversible seat is fixed on the side wall of the car through the automatic plug-pin mechanism when is folded. The seat cushion is abutted against the upper surface of a support frame on the bottom of the car in a horizontal state when the four-bar linkage long revers