Trolley

An upper supporting frame is connected to the upper portion of a bottom supporting frame, a seat supporting piece is connected to the upper supporting frame, a seat is arranged on the seat supporting piece, a clamping and locking device is arranged between the seat supporting piece and the upper supporting frame, and a push rod assembly capable of driving the seat supporting piece to rotate in the horizontal plane direction is further connected to the seat supporting piece. The push rod assembly is rotatably connected with the two sides of the seat supporting piece, so that the positions where the push rod assembly can stay comprise the pushing position capable of pushing the cart and the vertical position used for driving the seat supporting piece to rotate in the horizontal plane direction. A locking device capable of keeping the push rod assembly at a pushing position during locking is arranged between the push rod assembly and the seat supporting piece; a control assembly is further arranged between the s