French Single-Pin Escapement.
THREE-LEGG'D GRAVITY ESCAPEMENT.
The above illustration represents a regulator escapement as it would appear in a front view; the pallets are lifted by the three central pins. The locking teeth vary in size from one to nearly two inches. The horizontal pieces projecting from the top of the pallets form the adjustment for the arc of the pendulum.
The great advantages possessed by this escapement over all other gravity escapements, &c., are as follows:—
1. It requires no oil.
2. The angle of the detent planes reduces the friction to almost nil.
3. As the impulse and the unlocking are in one direction, the escapement is unlocked without recoil of impulse arms.
4. No impending force to the pendulum from inertia of impulse arms.