公开(公告)号：US3559763A

公开(公告)日：1971-02-02

申请号：US3559763D

申请日：1969-10-27

申请人： LAWNLITE CO

发明人： STERN MELVIN J

IPC分类号： E06C7/08

CPC分类号： E06C7/084

摘要： A ladder structure having a pair of parallel hollow rails, the hollow rails having slotted portions, a plurality of hollow steps having a rectangular cross section with tabs formed at the ends thereof received by the slotted portions and fastened to the sidewalls of the hollow rails.