Rotary crane

Rotary crane comprising a carriage;

• a telescopic mast on said carriage having an inner portion movable upwardly from a remaining portion of the mast and having an upper end;
• a pivotable boom mounted at said end;
• said boom including at least one end hinged element connected to said end, a boom tip and at least one hinged intermediate member interconnected between said hinged element and said tip;
• a hinged support mounted at the end of said inner portion;
• a rope system connected to said intermediate hinged member and said hinged element and deflected at said hinged support and connected to said carriage for supporting and folding said boom such that the boom is folded to be in a transport position or expanded to be in an operation position, said end hinged element, said intermediate member and said tip each being of triangular shape and including two lower chords spaced from each other and one upper chord, the chords in said end hinged element, in said member and in said tip being connected to each other respectively by rods;
• shackle means connecting the upper chord of the hinged element with the upper chord of the intermediate member such that they can pivot in a vertical plane with respect to each other, said shackle means being formed with an oblong opening extending in the direction of elongation of the boom when the latter is in its expanded position and including a pin insertable into said opening;
• and means for laterally interlocking the respective lower chord of the intermediate member with the respective lower chord of the end hinged element.