MANUFACTURE OF LADDER MADE OF ALUMINUM EXTRUDED MATERIAL

摘要

PURPOSE:To provide manufacture of a ladder made of aluminum which is suitable to be mounted on a cabin of a truck and excellent in corrosion resistance. CONSTITUTION:There are provided a process that an air hole which makes inside communicate to outside is provided in a hollow aluminum extruded material of the predetermined length and both ends of the extruded material is bent to form a frame member 12a, a process that a pair of bent ends of the frame member 12 are bonded together to form a frame 12 in the almost rectangular shape and a process that a step bar 13 made of the aluminum extruded material of the predetermined length is fixed to the frame 12 by welding.