Dynamic sealing up to 20 bar for directly operable rotating bezels with inner scale

The classic cockpit clock NaBo 17 ZM – long in service in military aircraft such as the Tornado and F-104 Starfighter as well as in helicopters like the Bölkow Bo 105 – was designed for the demanding conditions of flight operations: reliability, legibility and a straightforward operating concept were top priorities.

If this approach is to be consistently carried forward – for example, by transferring the characteristic rotating bezel construction with an inner scale to a modern wristwatch – a new technical challenge becomes apparent. While cockpit clocks traditionally do not require water resistance, it is indispensable for implementing this operating principle in modern mission timers and pilot’s watches.

The combination of direct rotatability and simultaneous water resistance creates a dynamic sealing situation that differs fundamentally from large static case seals at the case back or crystal.

With DSP Technology, we have developed a dedicated solution precisely to address this situation.

With model 717, we were the first to adapt the heritage of the traditional cockpit clock to a wristwatch: identical core functions combined with modern watchmaking technology – central chronograph seconds and minutes, a pilot’s rotating bezel with an inner scale, outstanding legibility – all in combination with water resistance rated at 20 bar.

DSP Technology was subsequently transferred to the 903 model series. This model in particular benefits from the technology due to the resulting significant simplification of the slide-rule function’s operation.