Pocket spring mattress
A spring mattress for beds is disclosed. In at least one embodiment, the spring mattress includes a plurality of strings which are interconnected side by side and include a continuous casing material with a plurality of separate pockets with coil springs enclosed therein. Moreover the casing material for at least some pockets is at least substantially airtight, thus providing a resistance to air being pressed out when the springs of the mattress are loaded, which, when subjected to a uniform load during a transition period, results in a gradually increasing depression of the spring to its depressed state. This results in a comfortable mattress, into which the user sinks gradually and which thus is comfortable and safe and allows the user to move easily. A corresponding method and device for manufacturing such a mattress are also described.
1. A spring mattress for beds, comprising:
a plurality of strings interconnected side by side, said strings including a continuous casing material with a plurality of separate pockets with coil springs enclosed therein, at least some pockets being made of an at least substantially airtight casing material and arranged to provide a resistance to air being pressed out when the springs of the mattress are loaded, resulting, with a uniform load during a transition period, in a gradually increasing depression of the spring to its depressed state.
2. A spring mattress as claimed in claim 1 , wherein the casing material is airtight and wherein at least one perforation is provided in each pocket.
3. A spring mattress as claimed in claim 1 , wherein the casing material is air-permeable to a limited extent.
4. A spring mattress as claimed in claim 1 , wherein the casing material, including any perforations, has an average air permeability, measured by a standard testing method, of from 0.15 l/m 2 /s to about 1.6 l/m 2 /s, with a differential pressure of 100 Pa through the casing material.
5. A spring mattress as claimed in claim 1 , wherein the transition period, during which a gradually increasing depression of the spring to its depressed state occurs, is in the range of 0.5-20 s, with the spring unit subjected to a uniform load of 20 N.
6. A spring mattress as claimed in claim 5 , wherein the transition period, during which a gradually increasing depression of the spring to its depressed state occurs, is in the range of 1-15 s, with the spring unit subjected to a uniform load of 20 N.
7. A spring mattress as claimed in claim 5 , wherein the transition period, during which a gradually increasing depression of the spring to its depressed state occurs, is in the range of 4-12 s, with the spring unit subjected to a uniform load of 20 N.
8. A spring mattress as claimed in claim 1 , wherein the strings are arranged side by side by interconnection of the surfaces of the casing materials.
9. A spring mattress as claimed in claim 1 , wherein the pockets of the strings are separated by welding.
10. A spring mattress as claimed in claim 1 , wherein some pockets of the mattress are arranged to provide a resistance to air being pressed out when the springs of the mattress are loaded, which resistance is different from that of other pockets.
11. A spring mattress as claimed in claim 10 , wherein pockets in the vicinity of the edge of the mattress are arranged to provide a resistance to air being pressed out when the springs of the mattress are loaded, which is greater than the resistance of pockets inwardly in the mattress.
12. A spring mattress as claimed in claim 10 , wherein pockets with different resistances to air being pressed out when the springs of the mattress are loaded are arranged so that different zones are formed in the mattress.
13. A spring mattress as claimed in claim 1 , wherein the casing is a weldable, textile material.
14. A spring mattress as claimed in claim 1 , wherein the strings comprise a plurality of separate pockets which are delimited from each other in a relatively airtight manner.
15. A spring mattress as claimed in claim 1 , wherein at least two neighbouring separate pockets of at least one of the strings are delimited from each other so as to allow a direct airflow between said separate pockets.
16. A spring mattress as claimed in claim 1 , wherein the casing material comprises a textile material coated with a substantially airtight layer.
17. A spring mattress as claimed in claim 16 , wherein the airtight layer comprises a plastic layer, such as a polyurethane layer.
18. A method of manufacturing spring mattresses for beds, comprising:
providing a substantially airtight casing material;
enclosing coil springs in separate pockets, the pockets being arranged in strings of continuous pieces of the casing material;
interconnecting a plurality of strings side by side; and
arranging, before or after the enclosing of the coil springs and the interconnecting of the strings, perforations through the casing material of at least some pockets.
19. A device for manufacturing spring mattresses for beds, comprising:
means for enclosing coil springs in separate pockets in a substantially airtight casing material, the pockets being arranged in strings of continuous pieces of the casing material;
means for interconnecting a plurality of strings side by side; and
means for arranging perforations through the casing material of at least some pockets.