Work on the new bus seat began in 2003 in response to the adoption of new safety requirements by several EU countries, among them the important UK and Italian markets. The new, stricter rules call for every seat to be fitted with a three-point belt. The safety belt has a major impact on the seat design as the stresses acting on the seat in an accident are greatly increased when the passenger is buckled up, and so the backrest must be made much sturdier than previously. In addition, the whole structure undergoes a strong lever effect.

“We started out using a conventional steel as we had done for earlier models, but we soon realised that this would make the seats too heavy,” says Joan Canals, head of engineering at Fainsa.

“To keep the weight down, the answer was ultrahigh strength steel, a material that was fairly new to us at the time.”

Along with the choice of the new high-strength steel came new ways of working, involving close collaboration between Fainsa and several of its suppliers. This has opened the door to new thinking.

The demands for light weight and improved safety were met with a design that combines extruded and pressed components of ultra-high strength steel.

“Many of the parts have to withstand very high stresses,” Joan Canals explains, “for example the legsand the brackets to which the backrest is fixed. For these we have chosen a sturdier hot-rolled ultra high-strength steel.”

An important part of the new design is the main backrest member. This is a hollow section of an advanced shape which provides the seat with integrated whiplash protection. Innovative forming technology was critical to this construction. Advanced high-strength hollow sections have only been available in the last few years, and the knowledge of how to work them is limited. The development of the new seat has extended the range of applications of this type of section.

Today the new seat is ready for the market, but for Fainsa this is only the beginning of the use of the new high-strength steels. The company, founded in 1935, has long and wide-ranging experience of the manufacture of vehicle seats and seat bases. The present CEO and owner, Juan Singla, has been with Fainsa ever since 1945, and explains “Our first products were bicycle and motorcycle seats. Today however we build passenger seats for buses and trains and are looking at the possibility of developing aircraft seats.”

“Our first products were bicycle and motorcycle seats,” Juan explains. “Today we build passenger seats for buses and trains, and we are looking at the possibility of developing aircraft seats.”