The example is from a forty-ton con

The example is from a forty-ton container crane boom hoist. This uses the same load spectrum found in Table 2. More specifically, the example is a gear mesh in a reducer, which drives a winch drum for the boom hoist, which raises and lowers the boom for the container crane. This is done via pulleys and a pivot.The boom is supported by folding support rods when the boom is all the way down (and the crane is in use). The winch must raise the boom out of the way when the crane is not in use, or to allow ships to move past the crane. Similarly, there is a support that locks the boom upright, once it is completely raised.The pulley system involves multiple wraps of cable, for a mechanical advantage. The load is constantly varying, since the centre of gravity of the boom changes with respect to the pivot and the angle of the cable changes.There are load variations from accelerations and decelerations at the start and end of travel. Wind, rain and ice build-up can also change the loading.This boom hoist uses a four-stage reduction gearbox, with a 175,3:1 overall ratio. This example is for the pinion of the fourth reduction low speed mesh, with the geometry, as given in Table C.1.