Detent escapement for timepiece

A detent escapement for a timepiece including an escape wheel fitted with teeth, a balance onto whose staff there are secured rollers including a large roller provided with an impulse pallet stone and surmounted by a first actuating finger-piece, and a small roller in the circular periphery of which a notch is made, and a blocking member in the form of a lever hinged on a pin, said blocking member carrying means for locking the escape wheel, a second actuating finger-piece and a follower ending in a beak arranged for cooperating with a rising edge of the notch of the small roller wherein the first and second actuating finger-pieces are rigidly secured respectively to the large roller and to the blocking member and arranged for cooperating with each other such that when the rollers are rotating in a first direction, the first finger-piece drives the second finger-piece to release the locking means from the escape wheel, the beak of the follower being then driven by the rising edge of the notch to re-engage the locking means in the escape wheel, and such that when the rollers are rotating in a second direction opposite to the first, the first finger-piece drives the second finger-piece to keep the locking means engaged in the escape wheel.