US3993122 Steps, stairs and the like
Cited prior art · Sven Gunnar Svenstam · Granges Essem AB · United States · 1976
Vasby, Sweden 3,157,358 11/1964 Birkemeier............................. 237/1 73) Assignee: Granges Essem Aktiebolag, FOREIGN PATENTS OR APPLICATIONS Vasteras, Sweden 236,086 10/1964 Austria............... .......... 52/189 22 Filed: Sept. 24, 1975 535,480 2/1955 Belgium................................ 52/220 481,691 3/1952