Beam
The foundry lifting-beam consists of a rectangular beam of wrought or cast iron, or wood, mounted with straps and ring to hang central in the block-hook of a crane. Notches sunk at equal intervals from each end allow of a balanced lift being taken with a pair of slings which fit the beam at one end and the flask-trunnions at the other, by which means the flask can be turned clear over before it is rested. By means of beam-hooks, chains may be hitched at any number of places along the sides. See SLINGS; BEAM-HOOK. A sound oak beam would require to measure four times the thickness of cast-iron to be of equal strength.
The table at page 44 will be found of great service when it is desired to construct a cast-beam for the purpose as described above, or for any other purpose for which cast iron beams are applicable.