Business A crane is a lifting machine generally used to lift and lower heavy materials and move them horizontally. It uses one or more simple machines to create a mechanical advantage thereby moving loads beyond the capability of a human. Cranes are commonly used in transport industries such as loading and unloading of freight. How did people actually come across cranes? Ancient Greeks were responsible in inventing the first construction cranes operated by men or donkeys. These cranes were used for construction of tall buildings. During the middle ages, harbour cranes were invented to load and unload ships and help with their constructions. The first cranes were made from wood but during the era of the Industrial Revolution, these wooden cranes were replaced with iron and steel. For a long time, these cranes were powered by men and beasts of burden, however, during the 18th and 19th century, the first mechanical power was provided by steam engines. crane trucks were created with a variety of forms. Each were built and designed for a specific use. Sizes also varied from the smallest jib cranes used in workshops to the tallest cranes used for building constructions. Larger floating cranes were also created to build oil rigs and salvage sunken ships. Unlike before, cranes were only designed for a vertical lift but as it developed, loads are moved to a considerable distance horizontally as well. There are different types of crane trucks used today; the Truck-mounted crane where a crane is mounted on a truck carrier provides the mobility o this type of crane. This type of crane is able to travel on the highways. No need for special equipment that transfers cane to other destinations. Truck cranes can lift from about 14.5 short tons to about 1.300 short tons. The second type is the Side lift crane, it is a semi trailer able to hoist and transport ISO standard containers. Lift is done with parallel crane-like hoist which can lift a container from the ground. Another type of crane is the Rough Terrain crane. The undercarriage is designed to have four rubber tires for pick and carry operations and rough terrain applications. Another type of crane used for maintenance work is the Railroad crane. It has flanged wheels for railroad use. Simplest form is a crane mounted in a flatcar. For bridges and port constructions, Floating cranes are used to load and unload heavy equipments. Other types include the crane vessels used during offshore construction and the aerial cranes which are helicopters designed to lift large loads. About the Author: 相关的主题文章: