Gear
Videos
A gear or gearwheel, also called a toothed wheel, is a rotating machine part typically used to transmit rotational motion or torque by means of a series of "teeth" that engage with compatible teeth of
Bronze gear with pawl from Luoyang, China, dated to the Warring States period (475–221 BC)
Modern model of a south-pointing chariot
Wooden cogwheel driving a lantern pinion or cage gear
A cast gearwheel (above) meshing with a cogged mortise wheel (below). The wooden cogs are held in place by nails.
Herringbone gear
Videos
A herringbone gear, a specific type of double helical gear, is a side-to-side, rather than face-to-face, combination of two helical gears of opposite hands. From the top, each helical groove of this g
This herringbone bevel gear was made by Citroën and installed around 1927 in the small Miřejovice hydropower plant on the River Vltava in the Czech Republic, connecting a Francis turbine to the generator. It worked flawlessly until 2011.
Citroën Type A final drive herringbone pinion and crownwheel
Engrenages 85.488