A common innerspring mattress consists of three components:

1. Upholstery layers, which encase the mattress core.

2. The spring core, also called innerspring unit.

3. The foundation, which many people call the base.

Spring mattress core

The core of the mattress is the most important part in the support of the
body. In most modern mattresses (except for the foam-only ones), it is made
up of steel coils springs, also known simply as coils. The spring mattress
core is also called innerspring. It provides support to the set. Proper
support is where the wire coils push back in response to weight deflection
to hold the body in alignment. The steel coil spring was invented during
the industrial revolution and was first patented for use in a chair seat
in 1857. Then, in 1871, Heinrich Westphal invented the innerspring mattress.
He lived in Germany and died in poverty, having never profited from his
invention.

Bonnell coils

These are the oldest and most commonly used. They were adapted from buggy
seat springs of the 19th century. They are still prevalent in most spring
mattresses. They have an hour-glass shape, and the ends of the wire are
knotted or wrapped around the top and bottom circular portion of the coil
(round-topped and self tied). The springs used by us are double tempered.

Foundations

Although in the past the foundation actually contained springs, increasingly
today it functions primarily to elevate the mattress.

Traditional wood foundation

It is usually made of softwoods such as pine or hard woods
such as poplar. It usually has seven or eight support slats, covered with
cardboard or beaverboard. This type of foundation, called by the industry
a zero deflection unit, increases the feeling of firmness or stability.
It is commonly known as a base.

Upholstery layers

The mattress core is covered by several soft materials, providing cushioning
and comfort. Some manufacturers call the mattress core by the name “Support
layer” and the cushioning materials by the name “Comfort layer”.
The “Comfort layer” can be divided into three sub-layers —
Insulator, Middle Upholstery and Quilt. Aside from the number and gauge
of the coils, the upholstery layers are used to differentiate the different
“qualities” of mattresses that manufacturers produce.

Insulator

This layer separates the mattress core from the upholstery, and it is
usually made of fiber or mesh, with the intention of keeping the middle
upholstery in place. It is commonly known as a STIFFY pad.

Middle upholstery

The middle upholstery comprises all types of materials on top of the insulator
and beneath the quilt. It is usually made from materials that give maximum
comfort — regular foam, chip foam, visco-elastic foam, felt, polyester
fibers, cotton fibers, convoluted (or egg-crate) foam, non-woven fiber
pads, flock fibres etc.

Quilt

The quilt is a top layer of the mattress made of light foam or fibers
stitched to the underside of the ticking, and provides the immediate soft
texture that the user feels when lying on a mattress. The quilt can be
firm or soft and plush. The protective fabric cover, which encases the
support and comfort layers of the mattress, is called ticking. It is usually
made to match the foundation and comes in a wide variety of colors and
styles. Most ticking is made of synthetic fibers like polyester, latex
and acrylic, or of natural materials such as cotton, silk & wool.
The ticking produces the look and feel of the mattress, so it is usually
soft to the touch and attractive to the buyer (at least that is what manufacturers
intend to create). We use woven Jacquards, Warp Knit Polyesters as well
as Stitch Bond.