Saarbrücken's watch manufacturer NIVREL cooperates with the Chair of Metallic Materials at Saarland University. The material scientists headed by Professor Ralf Busch experiment with metallic glass that has special properties: it is stronger than steel, yet elastic and malleable as plastic. Together, researchers and watchmakers have developed a special spring from a special alloy for so-called repeater watches.
Watches are more than just timepieces, they are pieces of jewelry, for which many people are willing to dig deep into their pockets. Especially the mechanics and the tiny components inside a mechanical watch are of interest for many technophiles: Small cogs that mesh exactly, or a delicate spring mechanism, which ensures that the watch shows the correct time. And even such traditional craftmenship as the watchmaking business relies on innovations. That's why the material scientists headed by Professor Ralf Busch from Saarland University cooperate with NIVREL, a watch manufacturer from Saarbrücken. A major scientific field of Professor Busch is the work with metallic glass, a material that brings along some interesting properties: it is stronger than steel, yet elastic and malleable as plastic. Together researchers and watchmakers have developed a special spring from a special alloy for so-called repeater watches.
A so-called repeater watch is a striking mechanism that allows to chime the time accousticaly when launching the function by pushing a button. "This mechanism goes back to a time when there was still no electricity," explains Ralf Busch, professor of metallic materials at Saarland University. "To read the time at night, you had to light up a candle in the frist place. Therefore this mechanism was developed, which could indicate the time by sound. "At 11:10 o’clock for example, the mechanism does 11 simple chimes and two double chimes. The simple strokes indicate the hours, the two double chimes indicate two five-minute intervals. What happens inside the movement is this: When the button of the repeater module is pressed a spring that is connected to the button activates a clapper that hits a large spring, the so-called gong. The vibrations generated with the gong spring are the chimes that indicate the hours and five minute intervals. Even though a mechanism like this one is no longer needed in times of electric light, many watch collectors care for such old techniques, mostly for nostalgic reasons.
The aim of the collaboration between the university researchers and Nivrel was to develop a new and better spring for launching the repeater meachsnism by using a new material. "Conventional steel springs so far were hard push, so it was quite difficult to push the repeater button," says William Hembree. The American has been working with Professor Bush since 2008, and was instrumental in the development of this spring. "We worked on a spring from a special metal alloy," Hembree explains further. "It is easier to move, and can provides a better energy storage." This alloy, for which the researchers from Saarbrücken claim a patent, consists of zirconium, copper, aluminum and niobium. It is strong as steel, but malleable as plastic. The new watch movement spring consists of exactly these properties, which ensure that the push button can be operated easier.