Method for producing an upholstery spring, upholstery spring, mattress, and upholstered furniture

Abstract

A method for producing an upholstery spring, such as for upholstered furniture or mattresses includes several steps. One of the steps includes at least regionally applying a heat-sensitive colour indicator to a spring steel wire before, during or after the bending of the spring steel wire. The spring steel wire is heated to at least the changeover temperature of the colour indicator. The upholstery spring is then finished.

1 . A method for producing an upholstery spring for upholstered furniture or mattresses, comprising the following steps:
 at least regionally applying a heat-sensitive colour indicator to a spring steel wire before, during or after a bending of the spring steel wire;   heating the spring steel wire to at least a changeover temperature of the colour indicator; and   finishing the upholstery spring.   
     
     
         2 . The method according to  claim 1 , wherein the spring steel wire is heated to above 250° C. for heat treatment and activation of the colour indicator. 
     
     
         3 . The method according to  claim 1 , wherein the spring steel wire is heated to a temperature between 280° C. and 320° C. for heat treatment and activation of the colour indicator. 
     
     
         4 . The method according to  claim 1 , wherein the colour indicator is applied to the spring steel wire by an immersion bath. 
     
     
         5 . The method according to  claim 1 , wherein the colour indicator is applied with a thickness between 0.05 μm to 1.5 μm. 
     
     
         6 . The method according to  claim 1 , wherein a copper-containing coating is applied as the colour indicator. 
     
     
         7 . The method according to  claim 1 , wherein the colour indicator is applied only in some regions to the spring steel wire. 
     
     
         8 . The method according to  claim 7 , wherein the colour indicator is applied to a central region of the upholstery spring, which central region deforms upon loading. 
     
     
         9 . An upholstery spring, produced by a method for producing the upholstery spring for upholstered furniture or mattresses, the method comprising the steps of:
 at least regionally applying a heat-sensitive colour indicator to a spring steel wire before, during or after a the-bending of the spring steel wire;   heating the spring steel wire to at least a the-changeover temperature of the colour indicator; and   finishing the upholstery spring.   
     
     
         10 . A mattress with an upholstery spring, where the upholstery spring is produced by the method of  claim 9 . 
     
     
         11 . A unit or piece of upholstered furniture formed with an upholstery spring produced by the method of  claim 9 . 
     
     
         12 . The mattress produced according to the method of  claim 10 , further comprising a step of providing a viewing window on a cover for the upholstery spring or a unit comprising a plurality of upholstery springs. 
     
     
         13 . The unit or piece of upholstered furniture produced according to the method of  claim 11 , further comprising a step of providing a viewing window on a cover for the upholstery spring or a unit comprising a plurality of upholstery springs.