US Patent 7086814 C-type column structure

A C-type column structure. The C-type column structure includes a hollow column, a column extending portion, and a support portion. The hollow column is formed with a closed U-shaped cross section, a curved portion, a trapezoid portion, a first end surface, and a second end surface. The curved portion is connected to the trapezoid portion to form the hollow column. The first end surface is opposite to the second end surface. The hollow column expands uniformly from the first end surface to the second end surface and has a predetermined thickness. The column extending portion is connected to the trapezoid portion and is adjacent to the first end surface. The support portion is connected to the trapezoid and column extending portions and is under the column extending portion.