No person shall place any barrels, casks, boxes, crates, castings, lumber or any other article on or over any of the sidewalks of the City, or suspend the same from any building, or place on the sidewalk any design, device or signboard, extending more than four feet from the line of the street or more than four feet six inches above the pavement of the sidewalk. Persons may use the sidewalk for the purpose of conveying their property to and from their premises, and no person owning property abutting thereon shall open or maintain any areaway or cellar opening without having the same securely covered.