Its composition consists on a spring block covered with more or less layers of over-stuff that isolate springs from the body at the same time that they give a comfort feeling.
The actual spring mattresses have technologically improved and still are number one in sales. They last much more and they have greater elasticity and a great level of transpiration. The problem is that after a time, springs start giving up, and becoming harder.
New models offer systems like pocket springs that guarantee an independent rest for each body area. Dual firmness adapts each side of the bed to different likings and differences of weight.
Types of springs in sprung beds: Details of the sprung bed picture (from a Flex bed):
- “Soft-Sense” spring
- Reinforcement of the perimeter
- Recycling polyether without CFC
- NT textile
- Recycling Polyether CFC
- Comfort System
- Thermal synthetic polyether
- Great upholstery quality
- Biconic springs (Low-intermediate quality). Springs have a double cone shape (that is, they narrow in the middle) that adapt better to the different weights of the body areas, called Bonell frame type.
- Cylindrical springs: Cylinder-shape springs. Normally pocketed to avoid sounds caused by friction.
- Compact frame: made with iron wires that cross the structure in zigzag. All over the perimeter, rhombus-shape springs are located to give greater firmness and hardness to the mattress.
At last, a good sprung mattress must have the firmness the user wants (firmness is not the same thing as quality), to be flexible, to distribute in an uniform way the stuffing, bed independence, to have handles, different kinds of reinforcements, ventilation valves and to resist tractions and as much as possible to resist fire.