Overhead cranes are in practice the most commonly used type of technical solution of lifting equipment – crane. The supporting steel structure (bridge) is the specific feature of overhead cranes. It consists of one or more main girders, that are at the end fitted with end trucks (with mounted travelling wheels).
Cross bars are formed by roll profiles or they are of box section – sheet weldment. Crane crab is travelling on the main girders, eventually it is underslung below them. Overhead crane travels by steel wheels on crane runway which is mounted on pillars. Electric supply is mostly solved by longitudinal main power line. Crane is controlled from cabin, by remote control or by pendant push-button panel.
Their gripping appliances are mostly suspended on ropes or rope systems of hoisting machinery – e.g. pulley blocks (with forged hooks), tongs, mechanical grabs, angle straps, various beams fitted with tongs, magnets, suction pads, suspensions, shackles, etc. E.g. motor grab, magnet, C-hook, etc. can be suspended on bottom block with hook.
Overhead cranes are designed and manufactured in wide range of hoisting capacities – from several hundred kilograms up to several hundred tons.