MAIN COUPLING FOR CONNECTION OF END LOWER CROSS-BAR UNIT WITH LOWER STRIP OF THREE-EDGED PRE-STRESSED COVERING FRAMEWORK UNIT Russian patent published in 2004 - IPC

FIELD: building units, particularly covering for heated industrial and agricultural buildings and structures. SUBSTANCE: coupling is formed as metal unit connecting cross-bars and includes tube and two corner plates welded to tube upper part and creating V-shaped profile. Cross-bars are connected to metal unit through metal corner plates. Coupling comprises metal rod inserted through metal unit. Metal rod has thread formed on one end thereof and is fixed by nuts. Two washers made of channel bar are arranged between nuts and metal unit. Helical spring is inserted between washers. EFFECT: increased strength and rigidity due to framework pre-stressing and forming of preliminary stresses "following" creep strains in framework. _