Screw mounting structure for platform ladder

The utility model discloses a screw mounting structure for a platform ladder, which comprises an auxiliary motor fixed on a hoistway mounting plate, the output end of the auxiliary motor is fixedly connected with the lower end of a screw through a screw fixing pipe, and the part, matched with the lower end of the screw, of the screw fixing pipe is a big-end-up conical pipe. A bearing capable of bearing an axial load is arranged at the position, close to the upper end, of the screw rod, and the bearing is arranged at the upper end of the screw rod through a fixing mechanism. An auxiliary motor is arranged at the lower end of the screw rod, and the auxiliary motor works to drive the screw rod to rotate during power failure, so that a driving nut on the screw rod drives the platform ladder to move downwards or downwards to a nearby floor together, and passengers in the platform ladder can escape conveniently; the bearing capable of bearing the axial load is arranged at the upper end of the screw rod, the lower e