United States Patent 3370836
Inventors:
Ashworth, James E.
Bartz, August L.
Publication Date:
02/27/1968
Assignee:
UNITED STATES STEEL CORP
Other Classes:
256/65.010, 29/513, 29/522.100
International Classes:
E04H17/10; E04H17/24; E06B11/04; E04H17/02; E04H17/14; E06B11/00