Technical innovations during the Second World War: an self-winding movement

Although a difficult time from a commercial point of view, because of the many obstacles and communication problems, as far as the economic situation was concerned the Second World War was quite a favourable period for the watchmaking industry. On the technical level, the period of the conflict proved to be a period rich in developments at Longines. Many calibres were also designed between 1939 and 1945 (although the creative pace proved to be slower than at the start of the decade), while simultaneously the brand developed new processes in the field of sports timing. But one important innovation was created in the workshops at the Saint-Imier factory towards the end of the war: the technical department researched the development of a calibre with automatic winding, a type which was beginning to find favour with the international clientele. Under the leadership of Alfred Pfister, the technical department made huge efforts in terms of research and development, on the one hand in order to design an self-winding movement – starting with a special movement blank – and on the other hand in order to create the tools necessary for its production. The development of a prototype, using a new winding technology never yest adapted to large-scale production, represented a considerable challenge requiring the participation of all the departments of the factory. In 1945, Longines introduced its first self-winding movement created in its own workshops : Calibre 22A. This circular movement measuring 21.5 mm in diameter was built simultaneously with subsidiary seconds or centre seconds, and was protected by numerous patents. In 1944, another development project was started in the field of chronographs. The technical department wanted to develop a calibre for a wrist chronograph that would be lighter than the models in production at that time. Following a lengthy phase of research and modification, in 1947 Longines brought out a mechanical manual winding movement fitted with a chronograph device, Calibre 30CH – the last wrist chronograph movement to be developed by the Saint-Imier factory.