Chinese Warring States Crossbow (475 BC - 221 BC)
One the most interesting examples of early Chinese technology is the crossbow. Crossbows evolved from earlier bows and arrows but fired small darts rather than the long arrows. In addition to superior penetration power, the cross bows had the advantage that energy was stored for later use. The crossbows were made of a bronze trigger mechanism that also held the dart, a short wooden bow, and the string or rope. They fired well designed bronze arrows with deadly force. The wooden bows deteriorate overtime but many examples of the bronze mechanisms have been found. Many of these are welded closed by corrosion but some are still functional mechanisms.
The following is an example of a heavy crossbow mechanism from the Warring States period. The mechanism is still functional and can be easily disassembled. The mechanism is made completely of bronze and has 6 pieces, three of which are moving parts. One of the most fascinating parts of the crossbow is the well designed center cam which combines a tappered cam shaft with a round shaft. For strength, this odd shaped piece had to be cast as a single piece, probably using a lost wax method.
Fully Assembled Cross Bow.
Full break apart.
Partial break apart showing the trigger and cam assembly.
Looking into the central cam shaft pieces. Left, cam. Right, cam rider.