Automatically folding and unfolding tower crane

An automated collapsible tower crane movable between a transport position and a working position, comprising:

• a telescopically extending mast with at least an upper telescopic portion with an upper end part, and a lower telescopic portion with a lower part rotatably anchored in a vertical plane to a lower base platform of the tower crane;
• a mast locking mechanism to lock the lower telescopic portion in a locked position in a substantially vertical plane with respect to a lower base platform of the tower crane;
• a telescoping system of the mast to telescopically extend and retract the mast between a retracted vertical position in which the mast is in a non-extended vertical position and an extended vertical position in which the mast extends upwards, wherein the telescoping system comprising a combination of cable and pulleys driven by a winch;
• a boom comprising a plurality of boom sections articulated by proximal and distal in respective rotary joints along respective rotation angles limited to substantially 180° around respective horizontal axes to stiffen the boom when it the boom is extended, the plurality boom sections comprising a first boom section, a second boom section and a third boom section, wherein the first boom section is articulated with the upper end part of the upper telescopic portion of the mast and at one end of the proximal portion of a second boom section;
• a boom reinforcement system for strengthening the boom in a working position;
• wherein in the transport position the boom sections are folded down over one another and on the mast in folding planes;
• wherein the boom reinforcement system acts independently of the combination of cables and pulleys driven by the winch of the telescoping system, and comprises hydraulic actuators hydraulically powered by hydraulic equipment for folding and unfolding the boom sections;
• wherein each proximal and distal rotary joint is associated with at least one of the hydraulic actuators arranged to unfold and fold boom sections relative to one another;
• and
• wherein the first boom section and the second boom section are articulated by a proximal rotary joint, the proximal rotary joint is formed by a joint body comprises a proximal part and a distal part which are joined by means of a hinge mechanism and means of a connector mechanism;
• and wherein the third boom section is articulated at the second boom section by a distal rotary hinge joint comprising:
• a primary horizontal joint axis that articulates the proximal portion of the distal section with the distal portion of the second boom section;
• a fixed lever arm immobilised on the proximal portion of the third boom section and presenting a free end with a secondary joint axis;
• a rotary angle arm with a first leg articulated with the primary horizontal joint axis and a second leg articulated with the secondary joint axis;
• and
• an intermediate part between the first and second legs of the rotary angle arm in which the distal end of the hydraulic actuator is articulated and wherein the proximal end of the hydraulic actuator is articulated in the distal portion of the second boom section.