Gravity self-locking trundle of platform ladder

The utility model discloses a gravity self-locking trundle of a platform ladder. The gravity self-locking trundle comprises a fixing base, a spring, an elastic piece and a trundle base with a pulley.Wherein the fixed seat is fixed at the landing end of a ladder leg of the telescopic ladder frame, the trundle seat is arranged below the fixed seat, the trundle seat is provided with a trundle columntowards the direction of the fixed seat, the upper end of the trundle column is provided with a mounting part inserted into the fixed seat, the spring is sleeved on the mounting part, and the middlepart of the trundle column is provided with a clamping part; one end of the elastic piece is arranged to be a fixed end fixedly connected with the fixed base, the other end of the elastic piece is arranged to be a movable end connected with the trundle column, and a wedge locking structure is arranged between the movable end and the elastic piece. And a clamping seat for limiting the posture of the movable end of the elasti