Cranes ~ these are lifting devices designed to raise materials by
means of rope operation and move the load horizontally within the
limitations of any particular machine. The range of cranes available
is very wide and therefore choice must be based on the loads to be
lifted, height and horizontal distance to be covered, time period(s)
of lifting operations, utilisation factors and degree of mobility
required. Crane types can range from a simple rope and pulley or
gin wheel to a complex tower crane but most can be placed within
1 of 3 groups, namely mobile, static and tower cranes.Cranes