| 摘要 |
<p>A tower crane with a self-assembling structure and a foldable and extractable tower having portions (14,15) hinged together at horizontal hinges (12,13), wherein a load arm (17) consists of at least one hinged portion (at 13), the tower (14,15) being hinged at a lower end to a bearing structure (10) with a rotation thrust block (19), at least one third portion (16) slotted into and capable of being extracted from one of the hinged portions (14,15) of tower, wherein the third top portion (16) has a smaller section with respect to the portion of tower (15) in which it slides through the collaboration of guide rollers (26,27) arranged both on the portion of tower (15) and on at least one top part (16), with an actuator (30) arranged to act between a support (42) arranged integral inside said hinged portion of tower (15) and a beam (41) integral with a lower end of said top portion (16). <IMAGE></p> |
