Incabloc
A sprung shock setting for the balance staff, developed in Switzerland in 1934. On impact the bearing jewel shifts within its sprung setting and protects the fine steel pivot of the balance from breaking.
At a glance
- Function
- shock protection for the balance staff
- First patented
- 1934, Switzerland
- Maker
- Universal Escapements / Portescap
- Components
- bearing jewel, cap stone, lyre spring
- Working principle
- elastic displacement of the whole bearing
- Rolex equivalent
- Kif Trior, Paraflex
- Seiko equivalent
- Diashock
- Installed
- practically every mechanical wristwatch since the 1950s
Incabloc is a system of shock protection for the balance staff, developed in Switzerland in 1934. The brand belongs to the Universal Escapements / Portescap group but is so widespread that "Incabloc" today is used almost synonymously with "shock setting." The system preserves the fine pivot of the balance staff in a fall — and so spares the movement from total failure.
Why a shock setting is needed
The balance wheel turns on two extremely finely ground steel pivots that run in ruby bearings. These pivots are only a few hundredths of a millimetre thick — just large enough to carry the oscillating balance, small enough to keep friction minimal. In normal operation that works perfectly. In a fall, however, very brief forces appear that can reach many times the watch's own weight. Without shock protection the fine pivot would break or the ruby would shatter — and the watch would stop immediately.
Before Incabloc, pivot fractures were one of the most common service findings; vintage movements without shock protection still show them regularly.
How Incabloc works
The system consists of a bearing jewel and a cap stone held together in a sprung lyre-shaped setting. In normal operation the bearing sits precisely centred and the balance staff runs without disturbance. On impact the entire bearing assembly displaces elastically — the jewel yields, the spring force absorbs the motion, and the system returns to its original position afterwards. The force is not transmitted to the fine steel pivot but redirected into the spring.
The effect is audible on the timegrapher: a watch with an intact Incabloc setting absorbs a light tap without an audible interruption in rate. A watch without protection or with a worn setting stops or degrades immediately.
Manufacturers and variants
Alongside Incabloc, several parallel shock-setting systems exist:
- Incabloc. The historical standard; common in ETA, Sellita, some Patek and many other Swiss movements.
- Kif Trior / Parechoc / Élastor. Competing system with similar function, used in Rolex and a number of premium movements.
- Paraflex. Rolex's in-house development in modern calibres; an evolved sprung shock setting.
- Diashock. Seiko and Grand Seiko use this system in their own movements.
Functionally all variants are equivalent — the respective brands have chosen different solutions for brand-strategy and construction reasons.
Service and wear
At our atelier in Munich the shock setting is checked at every complete service: seating of the cap stone, function of the spring, wear at the contact faces. The sprung lyre can widen or jam after many years; a gummed lubricant in the bearing reduces function. During service the jewels are cleaned, re-oiled and the spring is checked. Where needed the entire Incabloc unit is replaced — a short, routine intervention.
Frequently asked
- Today, yes. Essentially every mechanical wristwatch since the late 1950s carries Incabloc or an equivalent system — before that, shock setting was reserved for premium calibres. Vintage movements from the early 1950s and earlier often have none; that is why pivot breakage after a fall is a common service issue there. On a modern watch the absence of a shock setting points to a historical or decorative movement.