Incabloc

Small component, big impact

In a mechanical movement, many tiny components work together with great precision. The balance wheel, with its delicate arbor, is particularly sensitive. Its pivots are extremely thin and sit in jewel bearings. Theoretically, even a strong shock could cause damage here.

This is exactly where Incabloc comes into play. Incabloc is a shock protection mechanism that safeguards the balance wheel’s bearing. It allows the jewel to shift slightly in the event of an impact and then return precisely to its original position.

Why does a watch movement need shock protection?

Mechanical wristwatches are moved, set aside, worn, and sometimes accidentally bumped during everyday use. Without shock protection, the delicate pins of the balance staff would be particularly vulnerable. In the past, broken balance staffs were among the most common types of damage to mechanical watches.

A shock protection system does not completely eliminate the force, but it distributes and controls it more effectively. This prevents the most sensitive components of the movement from having to bear the full impact.

The History of Incabloc

The origins of Incabloc date back to the late 1920s. At that time, Fritz Marti developed the first systems to protect watches against shocks. In 1933, the name Incabloc was registered as a trademark, and in 1938, the system—featuring the distinctive Lyra spring—took on a form that remains closely associated with Incabloc to this day.  

This small spring is easily recognizable: it looks like a stylized lyre. Its function is to precisely re-center the bearing after a shock.

How does Incabloc work?

The Incabloc system uses a movably mounted combination of a bearing block and a cover stone. In the event of a shock, this bearing assembly can deflect within defined limits. This diverts the force away from the sensitive pins. The Lyra spring then returns the bearing to its correct position.

Incabloc itself describes how the shock is absorbed in two phases: First, the energy is absorbed by the bearing block, followed by re-centering via the spring. In the event of a fall from a height of about one meter, forces equivalent to a multiple of the balance wheel’s own weight can act on it.  

Incabloc in Modern Watch Movements

Today, Incabloc is one of the best-known shock protection systems in mechanical watchmaking. Many Swiss calibers feature this system or a comparable shock protection mechanism. CiRCULA also relies on Incabloc in various automatic movements. For example, the Sellita SW200-1 and the Sellita SW200-2 Power+ are equipped with Incabloc shock protection.  

What Incabloc Cannot Do

A shock protection mechanism makes a mechanical watch more robust, but not indestructible. Severe impacts, drops onto hard surfaces, or extreme vibrations can still cause damage. Incabloc primarily protects a particularly sensitive part of the movement—but it is no substitute for careful handling of a mechanical watch.  

Conclusion

Incabloc is a small but important detail in a mechanical movement. It protects the delicate balance wheel bearing, thereby contributing to the everyday reliability of modern automatic watches. Especially for functional watches, which are designed to be reliable and durable, good shock protection is a crucial factor in their robustness.