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The bipod crane of Heron

It consisted of two large (slightly inclined from the vertical) beams and one horizontal in the form of Π. The elevation was achieved with the use of a “pentaspaston” pulley with three “wheels” in the (top) fixed “pulley” and two in the (bottom) movable one. The machine was usually placed on rollers for its horizontal shifting. The traction force of the rope for the elevation of the load was emanated by animals or by a powerful manually
operated ground winch.