Coupling device for scaffolding

A coupler device, for connecting first and second building elements at a fixed right angle, the device comprising:

• a backbone plate;
• a first gate hingedly attached to a first side of the backbone plate for pivoting about a first fixed axis and configured to clamp a first tubular building element against the first side of the backbone plate by a first tightening mechanism including cooperating male and female threaded members;
• a second gate hingedly attached to a second side of the backbone plate, opposite the first side, for pivoting about a second fixed axis that is offset at a right angle from the first fixed axis and configured to clamp a second tubular building element against the second side of the backbone plate by a second tightening mechanism including cooperating male and female threaded members;
• wherein the first tightening mechanism and second tightening mechanism are respectively located beyond a plane defined by a side of the second tubular building element;
• wherein each tightening mechanism is configured to be exposed and accessible for tightening by a user from a direction facing the second side of the backbone plate, when the first and second building elements are fixed in place at right angles.