Frame structure, and structure

A foldable frame structure that is unfoldable into a planar 2N-sided polygonal shape, the frame structure comprising:

• 2N rods having an equal length and coupled to each other, the rods defining the planar 2N-sided polygonal shape, N being an integer equal to or larger than 2;
• coupling units that each include a pair of first main bodies, the first main bodies having notches, each of the coupling units disposed at a respective apex of the 2N-sided polygonal shape and couples a pair of the rods that are adjacent at the apex, the adjacent pair of rods at one of the apexes having end portions housed in the notches of the coupling unit disposed at the apex, the notches housing the end portions of the adjacent pair of rods such that each of the rods of the adjacent pair is rotatable about an orthogonal axis that is orthogonal to axes of both of the rods of the adjacent pair;
• and
• rotation units that enable each of the rods to rotate about the axis of the rod relative to at least one of two of the coupling units that hold both of the end portions of the rod, wherein
• the frame structure as a whole is foldable into a columnar shape with the rods pivoted about the orthogonal axis to minimize an angle between two adjacent ones of the rods while rotating about the axis.