BOOM SECTION, LIFTING BOOM AND TOWER CRANE

A boom section (1), the boom section (1) comprising: a boom frame (11); and mounting and dismounting assemblies (12), which each comprise a connecting member (122) and a drive member (121), which is fixed to the boom frame (11). The drive member (121) drives the connecting member (122) to make a telescopic displacement in a width direction of the boom frame (11), so that a trolley (2) is locked to the boom frame (11) or the trolley (2) is unlocked by means of the connecting member (122); thus, the locking or unlocking of the trolley is automatically completed, and the working efficiency of a tower crane is improved. Section de flèche (1), la section de flèche (1) comprenant : un cadre de flèche (11) ; et des ensembles de montage et de démontage (12), qui comprennent chacun un élément de liaison (122) et un élément d'entraînement (121), qui est fixé au cadre de flèche (11). L'élément d'entraînement (121) entraîne l'élément de liaison (122) pour qu'il effectue un déplacement télescopique dans le sens de la larg