Leaf spring
A leaf spring is a simple form of spring, commonly used for the suspension in wheeled vehicles. It is also one of the oldest forms of springing, dating back to medeval times.Sometimes referred to as a semi-elliptical spring or cart spring, it takes the form of a slender arc-shaped length of spring steel of rectangular cross section. The centre of the arc provides location for the axle, while tie holes are provided at either end for attaching to the vehicle body. For very heavy vehicles, a leaf spring can be made from several leaves staked on top of each other in several layers.
Leaf springs were very common on automobiles, right up to the 1970s, when the move to front wheel drive, and more sophisticated suspension designs saw car manufacturers use superior coil springs instead. However, leaf springs are still used in heavy commercial vehicles such as vans and trucks, and railway carriages.