Leaf spring
[2]: 16 The material and dimensions should be selected such that each leaf is capable of being hardened to have a fully martensitic structure throughout the entire section.
The shackle takes up the tendency of the leaf spring to elongate when compressed and thus makes the suspension softer.
The shackle provides some degree of flexibility to the leaf spring so that it does not fail when subjected to heavy loads.
The consequent stiffness, in addition to inter-leaf friction, makes this type of suspension not particularly comfortable for the riders.
Additional suspension components, such as trailing arms, would usually be needed for this design, but not for "semi-elliptical" leaf springs as used in the Hotchkiss drive.
As a substitute for dampers (shock absorbers), some manufacturers laid non-metallic sheets in between the metal leaves, such as wood.
Elliot's invention revolutionized carriage design and construction, removing the need for a heavy perch and making transportation over rough roadways faster, easier, and less expensive.
This design is characterized by fewer leaves whose thickness varies from centre to ends following a parabolic curve.
The intention of this design is to reduce inter-leaf friction, and therefore there is only contact between the leaves at the ends and at the centre, where the axle is connected.
A further development by the British GKN company and by Chevrolet, with the Corvette, among others, is the move to composite plastic leaf springs.
Nevertheless, due to the lack of inter-leaf friction and other internal dampening effects, this type of spring requires more powerful dampers/shock absorbers.
Some suspension designs use a Watts link (or a Panhard rod) and radius arms to locate the axle and do not have this drawback.
[2]: 1 Dr. Richard Lovell Edgeworth was awarded three gold medals by the Society of English Arts and Manufacturers in 1768 for demonstrating the superiority of sprung carriages.
Today leaf springs are still used in heavy commercial vehicles such as vans and trucks, SUVs, and railway carriages.
In many late 1990s and early 2000s trucks, the leaf spring is connected to a Hinkle Beam ball joint.
For example, the 1963 Chevrolet Corvette Sting Ray uses a transverse leaf spring for its independent rear suspension.
