Coupling member and housing

A coupling member for coupling at least two extending members to each other, the coupling member comprising:

• a first portion having a flat plate-like shape, the first portion having a first side extending straightly and a second side orthogonal to the first side and extending straightly;
• a second portion having a flat plate-like shape, the second portion being bent at the first side relative to the first portion, the second portion extending perpendicularly to an inner surface of the first portion;
• a third portion having a flat plate-like shape, the third portion being bent at the second side relative to the first portion, the third portion extending perpendicularly to the inner surface of the first portion;
• and
• a fillet portion having a flat plate-like shape, the fillet portion protruding perpendicularly to an inner surface of the second portion, the fillet portion being disposed to face the third portion, wherein
• a bend radius of an outer surface of the coupling member at the first side is equal to a bend radius of a surface of a first extending member facing the first side, and
• a bend radius of the outer surface of the coupling member at the second side is equal to a bend radius of a surface of a second extending member facing the second side.