Patent ID: 6996946

Claim:
In a composite structure comprising at least two coupled structures, wherein each of the at least two coupled structures comprises a plurality of pairs of scissors-connected tubular elements having extremities hinged in universal joints, said universal joints being integral delimited by substantially equal and parallel faces and forming four seats, each of the four seats in correspondence with a side face to accept hinged elements, the improvement comprising: each of said universal joints including a groove along each side of a larger face forming the four seats, said groove proximate to and parallel to a corresponding edge of each said side face; and a C-sectioned fixing element including two folded and inverted edges; the C-sectioned fixing element holding united two matching said universal joints such that the larger face of one of the two matching said universal joints is disposed in a direction opposite the larger face of the other of the two matching said universal joints, wherein one of the folded and inverted edges is inserted into one groove of one of the two matching said universal joints and the other of the folded and inverted edges is inserted into one groove of the other of the two matching said universal joints to snap the C-sectioned fixing element to the two matching said universal joints wherein the C-sectioned fixing element covers a substantial portion of a corresponding side face of superimposed universal joints and includes cut-outs corresponding to the seats for the hinged extended elements.