Patent ID: 7040803

Claim:
A detent escapement for a timepiece including: an escapement wheel; a pin of a balance on which is fixed a large roller fitted with an impulse pallet stone and a first actuating finger; a blocking member in the form of a lever hinged on a second pin, said blocking member carrying a locking pallet-stone, a second actuating finger and a follower which ends in a beak; and an elastic member acting on one of the first actuating finger and the second actuating finger to drive the other actuating finger and actuate the blocking member when the roller rotates in a first direction and to move around the other actuating finger without driving the roller when the roller rotates in a second direction opposite to the first direction, the pin of the balance further carrying a small roller in a circular periphery of which is a notch in which the beak of the follower penetrates when the locking pallet-stone releases from the escapement wheel, wherein return of the pallet-stone in a locking position is caused by a rising flank of said notch, said rising flank being slanted such that the beak climbs over said flank when the small roller rotates in the first direction.