page_title: Treadwheel crane
section_title: Ancient Rome
hierarchical_section_title: Treadwheel crane / History / Ancient Rome
caption_attribution_description: English: Reconstruction of a Roman Crane in Bonn, Germany Deutsch: Römischer Kran in Bonn (Nachbau) Ort: Grünanlage Römerstraße/Ecke Augustusring "Als Vorlage für die Reproduktion diente das Grabrelief einer römischen Bauindustriellenfamilie, auf dem ein solches Gerät teilweise zu sehen ist. Der Kran konnte vermutlich eine Last von sieben Tonnen heben und transportieren und seine Höhe von zehn Meter dürfte ausgereicht haben, die sieben Meter hohe Mauer des Legionslagers zu errichten. Eine sechsköpfige Mannschaft, ein Aufseher, ein Steuermann, zwei "Antreiber" in einem fast vier Meter hohen Laufrad und zwei Bremser sorgten für umweltfreundlichen Betrieb." (General-Anzeiger, 16./17.8.2003)
context_page_description: A treadwheel crane is a wooden, human powered, hoisting and lowering device. It was primarily used during the Roman period and the Middle Ages in the building of castles and cathedrals. The often heavy charge is lifted as the individual inside the treadwheel crane walks. The rope attached to a pulley is turned onto a spindle by the rotation of the wheel thus allowing the device to hoist or lower the affixed pallet.
context_section_description: The Roman Polyspaston crane, when worked by four men at both sides of the winch, could lift 3000 kg. In case the winch was replaced by a treadwheel, the maximum load even doubled to 6000 kg at only half the crew, since the treadwheel possesses a much bigger mechanical advantage due to its larger diameter. This meant that, in comparison to the construction of the ancient Egyptian pyramids, where about 50 men were needed to move a 2.5 ton stone block up the ramp (50 kg per person), the lifting capability of the Roman Polyspaston proved to be 60 times more efficient (3000 kg per person). There are two surviving reliefs of Roman treadwheel cranes, the Haterii tombstone from the late first century AD being particularly detailed.
  For larger weights of up to 100 t, Roman engineers set up a wooden lifting tower, a rectangular trestle which was so constructed that the column could be lifted upright in the middle of the structure by the means of human and animal-powered capstans placed on the ground around the tower.
caption: Reconstruction of a Roman treadwheel crane, the Polyspaston, at Bonn, Germany
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