They Exist(ed): Digital Before Electronics

In 2018, IWC celebrated its 150th anniversary with an unusual watch: the Tribute to Pallweber Edition “150 Years”. At first glance, it looks almost modern. Instead of conventional hour and minute hands, the time appears through windows: one number for the hour and two for the minutes.

That first glance must have been very different 130 years ago when Josef Pallweber, a watchmaker working in Salzburg, presented his invention: a mechanism for a watch that is completely digital - it shows the hour and the minute in numbers, instead of on a dial. The system used three rotating discs: one for the hours, one for the tens of minutes and another for the individual minutes. Pallweber's American patent describes this arrangement, with the minute disc advancing once every minute, the tens disc every ten minutes and the hour disc once an hour. The first watchmaker to adopt this revolutionary mechanism was IWC that began making watches based on Pallweber's system in 1884.

Around 20,000 were eventually made in Schaffhausen before production ended in 1890. However, convincing numbers to jump brings about quite a mechanical challenge. A normal watch movement turns its wheels continuously. A digital display needs the numbers to remain still and then suddenly move to the next position.

An article by Joseph Flores in Horlogerie Ancienne examines several surviving jumping-display pocket watches from roughly this period and shows that watchmakers found different solutions to the same problem. One uses a small spring that is armed and released at regular intervals. Another relies on interrupted gearing. The most interesting example has a 50-tooth wheel that initially seems incompatible with the required gear ratio. Looking closer reveals the trick. Some of the teeth are effectively bypassed and one leaf of the driving pinion is deliberately cut away. At a specific point in its rotation, this unusual geometry allows the display wheel to advance suddenly. Something that might look like damage is actually part of the mechanism. This also illustrates one of the difficulties with these early watches.

Moving relatively large discs instantaneously requires energy. IWC acknowledges that the original Pallweber watches suffered from a relatively limited power reserve because of the energy needed to advance their displays. More than a century later, IWC approached the same problem differently. The 2018 Tribute uses the hand-wound calibre 94200. Instead of simply reproducing the old mechanism, IWC gave the jumping display a separate wheel train and its own barrel. Every 60 seconds the mechanism releases it briefly to advance the single-minute disc. Every ten minutes the tens disc advances, and once an hour the hour display jumps. The main timekeeping train therefore doesn't have to provide the sudden bursts of energy required by the display.

That is what I find most interesting about the Pallweber rebirth story. The 2018 IWC is not a retro watch. It connects beautifully with a legacy of a mechanical challenge that watchmakers have been struggling with since the 1880s and solves it, without sacrificing the tradition and history it is built on.