Tower crane

A mobile tower crane, comprising mobile platform means carrying in combination a base mounting for a tower, a tower pivotally connected to said mounting for tilting movement between a vertical operating position and a substantially horizontal travelling position in which travelling position the tower is supported by said mobile platform means, and actuating means interconnecting the platform means and the tower for moving the tower between said positions, said combination of base mounting, tower and actuating means being such that the tower when in the operating position and without any bracing cables provides a firm support suitable for supporting load carrying means which is rotatable relative to the tower about the tower axis and which thereby in operation causes bending moments to be applied to said tower in various directions, and a jib structure carried by said tower, said jib structure comprising a turntable mounted on the top of said tower, said turntable including a rotatable part and a nonrotatable part, a jib support platform hingedly connected to the rotatable part of said turntable, power means for rotating said rotatable part of said turntable to cause slewing of the jib support platform about the longitudinal axis of the tower, a jib, a pivot mounting said jib on said jib support platform to allow luffing movement of said jib, power means connected between the jib support platform and the jib for causing said luffing movement, and power means connected between the movable part of said turntable and said jib support platform for folding the jib support platform relative to said turntable about said hinge connection, whereby the jib support platform and associated jib can be folded to an inoperative position along the side of the tower for travelling and unfolded to an operative position to the top of said tower.