IMPULSE PIN (ROLLER JEWEL)

The impulse pin (roller jewel) is a small pin made of ruby / jewel (synthetic corundum), with an elliptical cross-section, fixed (shellacked or glued) into the large roller, which itself is press-fitted onto the balance staff. It forms the connecting element between the balance and the pallets (lever): with each vibration, it enters the notch of the fork of the pallets (lever), receiving there the impulse that sustains the Oscillation, then causes the Pallets (lever) to swing, ensuring the Unlocking (drop angle) of the Escapement. Its elliptical shape and excellent Polished finish are essential: they guarantee a clean entry and minimal Set in the Fork, ensuring the safety and efficiency of the Escapement. It is also called the ellipse. The Impulse pin (roller jewel) also works together with the Dart (safety pin) and the small roller, which provide safety against Overbanking. Its precise angular positioning (roller setting) is part of the fine adjustments of the Escapement. Tiny yet critical, it is one of the contact points where the transmission of energy to the oscillator takes place.