Chang Ssu-Hsün

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Chang Ssu-Hsün

fl. 900s

Chinese inventor who is best known for his invention (in 976) of the chain drive for mechanical clocks. The first chain drive, designed by Philon of Byzantium in about 250 b.c., was used in a catapult. Mechanical clocks did not appear in Europe until the early fourteenth century, and the first Western chain drive was not developed until 1770.