# Leaf Springs

Either a simple beam used as a spring or laminations of steel.

A slightly arched steel band used as a spring. An axle is suspended from the approximate center of the steel band; the bending of the band provides a cushioning effect.

The term is also used to refer to a bundled set of leaf springs. Each leaf is fastened to the next through a bolt placed slightly ahead of the centre of the spring. As the spring flexes, the leaves slide over each other; the resultant friction provides a dampening of the oscillations produced by large spring deflections.

### Semi-elliptic laminated leaf spring

where
E = Youngs modulus [Nm-2]
n = number of leaves
b = width of leaves [m]
t = thickness of leaves [m]
l = span [m]

### Quarter-elliptic laminated leaf spring

where
E = Youngs modulus [Nm-2]
n = number of leaves
b = width of leaves [m]
t = thickness of leaves [m]
l = span [m]

### Elliptical Leaf Spring

Two sets of semi-elliptic laminated leaf springs mirrored together with rotating joints at each end.

The image shows the elliptic leaf spring on a horse drawn cart.

### Arch

The curve on a leaf spring. If the center is lower than the ends it is called positive arch. If the center is higher than the ends the arch is negative.

### Berlin Eye

Refers to the eye of a leaf spring when the eye is upturned.

### Cantilever

When used with regard to leaf springs, the front cantilever is the portion of the spring that extends forward of the U-plate; the rear cantilever is the portion of the spring extending back to the shackle.

### Compression Shackle

A short arm connecting the rear of the leaf spring to the frame which limits travel by compression.

### Downturned Eye

Refers to the eye of a leaf spring when the spring turns down to form the eye.

### Eye Diameter

The inner diameter of the eyelet at each end of a leaf spring; this provides an attachment point to the frame (front) or to a shackle (rear).

### Inactive Length

The central portion of a leaf spring that is prevented from flexing by the U-plate.

### Splayed Springs

Leaf springs that are not parallel to the centreline of the vehicle in the plan view.

### Spring Top Leaf Thickness

The thickness of the topmost leaf in a multiple-leaf spring.

### Tension Shackle

A link attached to the rear eye of a leaf spring and to the frame of the vehicle.

### Tie Bolt

A fastener which passes through the leaves of a leaf spring, holding it together.

### U-bolt

The U-shaped bolt connecting a leaf spring to the axle.