It consisted of a single large beam that had two “pulley-wheels” at its vertex and at the base. Its inclination was achieved with the help of three balancing ropes that were tautened or loosened with the help of small winches.

A rope was wrapped at equal distances around the beam, which served to strengthen it, but also as a ladder for urgent repairs.

The beam was usually placed on a base with rollers for its horizontal shifting with a dent in the centre which ensured its articulation. The traction force of the rope for the elevation of the load was emanated by animals or by a powerful manually operated ground winch. It was used for the rapid implementation of minor work.

SOURCES: Heron of Alexandria, Mechanics, Pappos of Alexandria, Mechanics.