Impulse Pin
The ruby pin of the lever escapement which, entering the notch of the lever, unlocks the escape wheel and then receives impulse from the lever and passes out at the opposite side.
How to true a balance, repair a chipped dial, temper a spring or test a stone — the working bench-book of the American watch trade, arranged A to Z.
The ruby pin of the lever escapement which, entering the notch of the lever, unlocks the escape wheel and then receives impulse from the lever and passes out at the opposite side.