Toothed gear
Engranaje dentado
- Date
- c. 270 BCE · confidence low
- Place
- Alexandria, Egypt
- Credited to
- Ctesibius and the Alexandrian mechanical school
- People
- 👤 Ctesibio284 BCE–221 BCE
- Field
- Tools
⚠️ Disputed: the sources disagree.
What it is
A toothed wheel that transmits motion and torque to another wheel, changing speed, direction or plane of rotation. A fundamental component of every complex machine.
The oldest surviving gears are Chinese, from the Warring States period (4th century BCE, Luoyang Museum); in the West, the Aristotelian Mechanical Problems (c. 330 BCE) already mention them, before Ctesibius.
What it led to
- Water mills with a change of rotation plane
- Astronomical calculators and clocks
- Odometers, automata and cranes
- The theory of machines and power transmission
Built on
Made possible
- Advanced water clock (Ctesibius' clepsydra)c. 270 BCE
- Watermill (water wheel)c. 250 BCE
- Antikythera mechanismc. 100 BCE
- Vertical-wheel geared watermill (Vitruvian mill)c. 25 BCE
- Aeolipile and Heron's automatac. 60 CE
- Al-Muradi's epicyclic and segmental gearsc. 1050
- Su Song astronomical clock tower1092
- Mechanical weight-driven clockc. 1283
- Vitruvius's odometer
- Advanced water clock
- South-pointing chariot