Technique → Watch case

CROWN

With the winding stem, it establishes the connection between the exterior of the case and the movement within the case. By rotating the crown, the watch user can wind the watch, set the time, or adjust the date, to name just the main functions it can perform. The various functions typically assigned to the crown can be arranged in a staged manner, much like the gears in an automobile gearbox. By pulling the crown, one can transition from the winding position to date adjustment. Pulling the crown further into a third position allows for the correction and adjustment of the displayed time. In nearly two centuries of existence, the crown has evolved and seen various types of construction. Nowadays, most crowns are waterproof and are directly screwed onto the end of the winding stem.

When the crown is pulled into its different positions (date correction, time setting, etc.), it slides on a tube directly inserted or screwed into the middle part. The crown tube limits its lateral play to reduce the risk of the winding stem breaking, providing more comfort, and ensuring the seal between the crown and the case. For even better waterproofing, especially in technical diving watches, a thread or bayonet on the tube is used to lock the crown onto the tube by compressing the sealing gaskets that connect them.

For ergonomic reasons, the crown is usually located at 3 o’clock, although no rule dictates this practice.

Due to its role as a physical connection and its prominence on the periphery of the case, the crown is an excellent design element and a means of decoration.

It was Adrien Philippe who invented the winding crown (and consequently, the winding stem) in 1842. This invention led to his meeting with Norbert de Patek two years later, and the rest, as they say, is history.

At that time, the crown only served to wind the watch’s mainspring and had no other function. In 1847, another illustrious watchmaking inventor, Antoine Le Coultre, patented the first keyless winding system. From then on, the crown allowed for both time setting and mainspring winding.

In 1926, Rolex introduced the first waterproof watch, and its founder, Hans Wilsdorf, patented a waterproof crown. To achieve this, he had the idea to screw the crown onto its tube. This way, the crown compresses the gasket, improving its waterproofing. This system still predominates in the production of crowns for sports watches and, logically, especially for diving watches.

The technical part of a crown is often made of steel, while the visible aesthetic part can be made from nearly any material (metals, sapphire, minerals, plastics, rubber, etc.) and is securely fixed to the technical part as a cap.

The crown can be engraved (for decoration or brand logos), set with a medallion (logo), or even feature gemstone settings.

The production of crowns is typically handled by specialized subcontractors. However, artisans can craft relatively simple crowns using a lathe, a milling machine or even an automatic lathe. For more intricate crowns or better cost control, artisans may acquire standard or custom technical components from specialized subcontractors and only produce the aesthetic cap.

Most of the crowns are produced on an industrial scale. In this method, turning is the preferred technique. The crown and its various components fit perfectly into the dimensions and operations suitable for automatic lathe. For the cap or a medallion to be set, techniques like electro-erosion or stamping may be employed. Once machined, the crown is decorated (diamond-cutting, satin finishing, microblasting, gem setting, etc.) and then assembled.

New technologies in this context exclusively concern the aesthetic part of the crown (its cap). New materials (plastics, composites, ceramics) or vulcanized rubber overmolds involve the latest technologies in terms of injection, machining, and assembly.