Cable reels for cranes
Drums on cranes serve for a navivka of ropes by means of which lift and lower freight. On a surface of a drum there are spiral flutes (streams) thanks to what the cargo rope when winding lays down the correct ranks. Flutes on width do a little more than diameter of a cargo rope that he laid down freely and did not touch its sidewalls.
Flutes promote the correct laying of a rope and prevent friction between its running branch and already laid round. On one half of a drum they are directed to the right, and on other half — to the left. It is necessary in order that the freight suspended on two branches of a rope rose and fell down without horizontal movement along a drum.
Drums produce cast of cast iron and steel or welded of sheet steel. Cast drums it is heavier welded for 40 — 50%. All rounds of the rope wound on a drum have identical diameter that at a constant angular speed of a drum allows to receive the constant speed of a navivka. Fastening of a rope on a drum has to be reliable and at the same time convenient for fast change of a worn-out rope.