Models of Hybrid Springs for Ergonomic Seats and Mattresses

An ergonomic seat or mattress has to provide optimal and uniform support for the body of a man or a woman with similar or slightly differing size centiles. It is a common opinion that spring systems in upholstered furniture are much more durable and more user-friendly than foam systems. The aim of this study was to develop a new construction of an upholstery spring of bilinear stiffness. On the basis of the conducted studies and analysis of their results, it was shown that traditional bonnell and barrel springs exhibit linear stiffness within the range of deflections of up to 70 % of their initial pitch. New spring designs change stiffness already at deflections of 34% of their pitch. Thanks to this fact they may be used in designs of seats and mattresses for individual users, patients or disabled individuals.