Telescopic boom of crane

摘要

The invention relates to building the cranes. A telescopic boom of crane contains telescopically connected fixed and mobile sections, fixed stops in the apexes of fixed and intermediate mobile sections and a block-cable pulley. Running blocks of the latter are installed at the apex of fixed section and at apexes and bases of intermediate mobile sections. One end of the cable is connected to the tension drum installed at the basis of boom with possibility of winding-unwinding the branch of cable from the block of the apex of fixed section. The cable is reeved on the tension drum with possibility of simultaneous winding-unwinding of the second branch of cable for arrangement of the boom in the direction opposite to direction to the motion of the branch of cable from the block of the apex of fixed section. The second branch of cable is connected by the end to the most distant mobile section from the basis of boom through a tightener. Technical result: increase of the efficiency of extension and retraction of mobile sections.