Heron of Alexandria

Michael Lahanas

Hρων ὁ Ἀλεξανδρεύς

Heron von Alexandria, Biographie, Erfindungen, Wissenschaft

Part 2

Fire extinction Machine

Two Piston Machine for continuous flow of water for fire extinction, probably a work of Ctesibius (c. 250 BC) that Hero improved.

Sequence Control

Heron of Alexandria described a mechanism or apparatus that made use of the so called "sequence control" mechanism. This mechanism used drums in which pins and gears were mounted to control events that 'laid ahead'. Sequence control gives means to foretell the outcome of a sequence of events in advance, without influencing the outcome directly. Examples of sequence control are a music box with a drum on which pins are attached that strike against the teeth of a comb. Teeth that have predefined lengths and thus possess their own tone. By striking teeth in a predefined sequence a melody will sound. Sequence control is defined as a lower generation of computer programs.The operator feeds machines like that with certain limited input and lets the machine run on its own without external control for the outcome: actions to move mechanical contraptions, music or calculations.

Heron Screw Press

Use of Wind Power

From a PhD Thesis about the history of the Organ (Author unknown but will provide if found):

The power supply for the wind-driven organ relies on the transfer of motion from the “broad arms like the sails of a wind-mill” to the piston mechanism. The arms are attached to one end of a rod, which is supported such that it turns freely. As the arms turn in the wind, the rod conveys a rotary motion to a gear-like pegged disk fitted tightly on the opposite end. The revolving pegs make contact with a lever attached by a pin to the piston rod, causing the piston to be raised as each peg engages the rod mechanism. When the peg advances beyond the lever, the lever is released and the piston descends in the cylinder. The falling piston compresses the air, forcing it out into the base of the cylinder, up through a connecting tube, and into the box on which the pipes stand. As the key mechanism is activated, air is released into the pipes, causing “the sound of a flute” to be produced. To assure a steady supply of air, the windmill frame can be turned directly into the prevailing wind. the wind-powered organ is the only known documented windmill type mechanism in antiquity. Wind power does not reappear in Western civilization until the twelfth century. ....from an historical point of view, these instruments incorporate a manual keyboard, which as an artifact seems to be without precedent. Finally, the gear-like mechanism of the pegged disk attached to the windmill shaft is designed to transfer power from the rotating shaft to the reciprocating piston, thus converting circular to reciprocal motion.

at the Ruskin School of Art and Drawing, Oxford, February 17, 2004 Oxford University