Device for folding a crane jib with nesting elements

A device for the motorized folding and unfolding of a crane jib made up of elements joined together by articulation, with two consecutive jib elements, the two consecutive jib elements being a rear jib element and a front jib element which can nest one inside the other when the jib is in a folded position, the two consecutive jib elements having respective cross sections which allow them to nest, the front jib element and the rear jib element being articulated together about a first horizontal axle located approximately mid-way up the jib, the front jib element having, in its rear part, lateral guides shaped as arcs of a circle, the lateral guides housing a second horizontal axle connected to the rear jib element, the device comprising:

• a double-acting ram located in the vertical mid-plane of the crane jib and articulated by a first end, about a third horizontal axle, to the rear jib element in an upper member or members of the rear jib element;
• a first link rod articulated, by a first end, to a second end of the double-acting ram and articulated, by a second end, to the rear part of the front jib element in the lower part of the front jib element;
• and
• a second link rod articulated, by a first end, to the second end of the double-acting ram and articulated, by a second end, to the front part of the rear jib element in the lower part of the rear jib element, the second link rod leaving space for the passage of the second horizontal axle housed in the lateral guides.