In piston engine engineering, a balance shaft is an eccentric weighted shaft which offsets the vibrations of unbalanced engines.
The Balance Shafts
The balance shafts are on either side of the crank on the same plane. They rotate in opposite directions at twice the speed of the crank. There are weights on these shafts. When both weights are pointing upwards it exerts an upward force, and the opposit when downwards, when the weights point away from each other or towards each other, they cancel each other out. This allows it to cancel each of the four up and down shaking forces that act on the engine during one rotation of the crank.
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