Cranes (Invention and ancient use)
Introduction
A crane (also güinche,[1] guinche,[2] or titan)[3] is a machine designed to lift and distribute loads and construction materials in space suspended from a hook. The crane is one of the first machines that existed in the world. As a general rule, they are devices that have grooved pulleys, counterweights, simple mechanisms, etc., to create a mechanical advantage and be able to move large loads.
The first cranes were created in ancient Greece, powered by men or animals. These cranes were mainly used for the construction of tall buildings. Later, larger cranes were developed using pulleys to allow the lifting of greater weights. In the Early Middle Ages they were used in ports and shipyards for the stowage and construction of ships. Some of them were built anchored to stone towers to provide additional stability. The first cranes were built of wood, but since the arrival of the industrial revolution the most used materials are cast iron and steel.
The first mechanical energy was provided by steam engines in the 19th century. Modern cranes generally use internal combustion engines or electric motor and hydraulic systems to provide much greater forces, although manual cranes are still used on small jobs or where power is uneconomical.
There are many different types of cranes, each tailored to a specific purpose. Sizes range from the smallest jib cranes, used inside workshops, to tower cranes, used to construct tall buildings, to floating cranes, used to construct oil rigs and to rescue stranded ships.
There are also machines that do not fit the exact definition of a crane, but are generally known as such.
History
Contenido
La grúa es la "evolución" del puntal de carga que, desde la antigüedad, se ha venido utilizando para realizar diversas tareas. Aunque sus fundamentos fueron propuestos por Blaise Pascal en pleno Barroco, existen documentos antiguos[4] donde se evidencia el uso de máquinas semejantes a grúas por los Sumerios y Caldeos, transmitiendo estos conocimientos a los Egipcios.[5][6].