Cranes- Its types and classification...

Cranes- Its types and classification A crane is a machine which is having a hoist with a longitudinal and cross movement. The hoist of a crane consists of wire rope and hook. The crane is used both for lifting and lowering materials, and to move them horizontally. Cranes uses one or more simple machines to create mechanical advantage and thus move heavy loads. Many factors are taken into consideration while selecting a crane. These factors include lifting capacity, crane use and application and the number of work cycles that the crane is required to undergo. Types of cranes Cranes are of many types. Some of them are given below. Overhead cranes – An overhead crane is also known as a bridge crane. It is a type of crane where the hook and the line mechanism runs along a horizontal beam that itself runs along two widely separated rails usually in a long factory building and runs along rails along the building’s two long walls. These cranes include a hoist to lift the items, the bridge, which spans the area covered by the crane, and a trolley to move along the bridge. Overhead cranes typically consist of either a single beam or a double beam construction. These can be built using typical steel beams or a more complex box girder type. Double girder bridge cranes are more typical when needing heavier capacity systems from 10 tons and above. The advantage of the box girder type configuration results in a system that has a lower deadweight yet a stronger overall system integrity. A typical overhead crane is shown in Fig 1. Fig 1 A typical overhead crane Gantry crane – A gantry crane has a hoist in a fixed machinery house or on a trolley that runs horizontally along rails, usually...