EXHIBITS > The elevating mechanisms of the ancient Greeks >
The three-mast crane
It consisted of three inclined beams which shaped a tripod. The load was suspended via block and tackle at the top of the machine and was lifted with the help of a horizontal rotating axle ("reel"). The axle was supported in bearings ("tortoise-like cases") on the two front beams and was turned with the help of levers. For the reduction of friction, the axle had two small metal shafts at both sides rotated to specific receptors within the "turtle".
SOURCES: "Vitruvius, On Architecture", Pappos of Alexandria, Mechanica", "Heron of Alexandria, Mechanica"