Today, we are going to look closer at cranes – not the birds, but the machines, though the machine took its name after the bird because of the resemblance of its design to the long neck of the crane.
Cranes might seem a fairly modern invention, but in fact they were invented by the Ancient Greeks circa 6th century B.C. and firstly recorded in print in Mechanical Problems, attributed to Aristotle.
The simplest Roman crane, the Trispastos, could raise 150 kg operated by a single man.
The Polyspastos, on the other hand, when worked by four men at both sides of the winch, could lift 3000 kg or 6000kg when the winch was replaced by a treadwheel.
And the Romans did not stop there, constructing wooden lifting towers able to lift up to 100 tonnes.
Cranes did not advance much further during the Middle Ages, yet by the 15th century cranes powered by windlasses appeared. At the time, they were rarely places on the outside of buildings, rather within the construction and dismantled piece by piece to be moved to and assembled back at the next construction level.
The treadwheel cranes remained in use until the mid 1800s, with the most powerful harbour cranes, built in the London docklands in the 1850s, having two treadwheels of up to 3 meters wide, each walked by 3 to 4 men.
The first crane where wood was replaced with iron was constructed in 1834, in 1838 the first hydraulic water powered crane was designed, and in 1851 the steam powered crane enabled the lifting of virtually any weight.
The term crane entered the English language circa 11th century, to name storks and other large grallatorial birds, through common Germanic and deriving from Greek and Latin.
And when it comes to the first mention related to the crane machine, we find it in regard to the profession of a crane keeper in Henry Thomas Riley’s Memorials of London and London Life in the 13th century where under the names of London traders he lists: “Creneman, or Craneman, perhaps the keeper of the public crane, 1300 (B 42).”
As for the crane machine, the first record comes from the Scottish poem, The Brus, written about 1375 and giving a historic account of the actions of Robert the Bruce in the Scottish Wars of Independence.
The first English chronicler to record the needs of London of the building of a new crane is Richard Arnold, who in 1503, in his The Customs of London: Otherwise Called Arnold’s Chronicle includes a letter to the Mayor of London calling that he keeps his promise: “That they should make..a crane sufficient and able to take vp from the water of Thames the weight of a tonne”.
In comparison to the needs of 16th century London, today, the world’s strongest crane, the Taisun Gantry Crane, housed in Shandong Province in China, has a safe working load of 20,000 metric tonnes and holds the official lifting record registered in the Guinness Book of World Records.