Incabloc is the registered trade mark for a watch anti-shock system which acts to protect the balance-staff pivots. It was devised by Fritz Martis and first registered in July 1933. The system incorporates a tiny spring known, because of its shape, as a lyre-spring. In the event of an impact this spring acts to instantaneously and accurately re-centre the balance staff pivots.
Earlier efforts at creating shock resistant watches required 2 lyre-springs in order to cope with both lateral and axial shocks but Fritz Marti’s new conical shaped bearing block system enabled lateral impacts to be transformed into the axial direction eliminating the need for a second spring.
There is a variety of anti-shock systems but the Incabloc system is still fitted to the majority of Swiss watches.