The ETACHRON Regulator
The ETACHRON regulating system (and similar designs) use rotating "blocks" attached to the hairspring stud and a movable regulating arm. The regulator effectively shortens or lengthens the hairspring and can be rotated to maintain perfect contact with the spring. Similar systems are employed by many watches, some of which use other regulating and indexing systems.
ETACHRON has officially been available in four versions:
- With a pointer on the balance cock
- With an eccentric screw corrector on the balance cock
- With the Valjoux corrector on the balance cock
- With no pointer or screw corrector
This has lead to some confusion, with some sources claiming that only the movable stud and rotating block is "ETACHRON", since these are present on all such movements. But ETA documents are clear that all of these components are part of the ETACHRON system.