A Bell Crank Bush Signa is a type of crank that changes motion through an angle. The angle can be any angle from 0 to 360 degrees, but 90 degrees and 180 degrees are most common. Bell cranks translate the vertical motion of the wheel into horizontal motion, allowing the suspension to be mounted transversely or longitudinally within the vehicle. The name Bell Crank Bush Signa comes from its first use, changing the vertical pull on a rope to a horizontal pull on the striker of a bell.