Automatically starting and secured detent escapement for a timepiece

1. A horological detent escapement adapted to be integrated in a horological movement and arranged to transmit a torque originating from an energy source of said horological movement to an oscillating regulating organ of said horological movement, the regulating organ of the horological movement comprising a first mobile body, the escapement comprising:

a second mobile body configured to cooperate with said first mobile body and configured to be stopped by the first mobile body in a first or a second position defined respectively by a first and a second banking against which said second mobile body comes to rest, the second mobile body comprising an indirect impulse transmitter; and

an escapement wheel, said escapement wheel being arranged so as to transmit, during a half-phase of each oscillation of the regulating organ, a torque to said regulating organ via a direct impulse;

wherein said indirect impulse transmitter of the second mobile body is arranged and positioned so as to be, during the whole oscillation of the regulating organ during the normal functioning of the escapement, out of contact with the escapement wheel, while being capable of coming into contact, during another half-phase of each oscillation of the regulating organ during which the escapement wheel does not transmit torque to the regulating organ by means of a direct impulse, with the escapement wheel, so as to transmit a torque to said regulating organ of the horological movement by means of an indirect impulse, via the second mobile body, following an inadvertent movement or an inadvertent stoppage of the horological movement.

2. The horological detent escapement according to claim 1 , wherein said energy source comprises a barrel spring and said regulating organ comprises a balance.

3. The horological detent escapement according to claim 2 , wherein said first mobile body of the regulating organ of the horological movement comprises a roller carried by an axis of the balance.

4. The horological detent escapement according to claim 3 , wherein said second mobile body of the escapement comprises pallets, said roller being adapted to cooperate with said pallets.

5. The horological detent escapement according to claim 1 , wherein said escapement wheel comprises a number of teeth situated in the range of 13 to 19.

6. The horological detent escapement according to claim 3 , wherein the first mobile body comprising said roller comprises a circular plate surrounded by a skirt having internal and external walls, said skirt having a notch arranged so as to be traversed by a finger fixed on the second mobile body, the second mobile body being stopped in the first position when it is resting on the first banking and its finger adjoins the internal wall of the skirt and being stopped in the second position when it is resting on the second banking and its finger adjoins the external wall of said skirt.

7. The horological detent escapement according to claim 6 , wherein said second mobile body comprises at least one securing and guiding surface oriented in a direction substantially opposed to said finger so as to secure said second mobile body during a functioning phase of the escapement during which the finger fixed on the second mobile body traverses the notch of said skirt of the first mobile body.

8. The horological detent escapement according to claim 7 , wherein said securing and guiding surface is arranged and positioned so as to be, during an impulse phase of the balance by the escapement wheel, at an exterior periphery of a trajectory of the escapement wheel of said escapement, so as to be capable of coming into contact with said escapement wheel in order to secure the second mobile body, respectively pallets comprised by said second mobile body, preventing it from returning, following an inadvertent movement, on the trajectory of the escapement wheel.

9. The detent horological escapement according to claim 1 , wherein said second mobile body of the escapement is given an angular movement or a rectilinear movement.

10. The horological detent escapement according to claim 1 , wherein said indirect impulse transmitter comprises an indirect impulse pallet-stone situated substantially close to the pivoting axis of said second mobile body.

11. The horological detent escapement according to claim 10 , wherein said indirect impulse pallet-stone is made from a low-friction and low-wear material.

12. The horological detent escapement according to claim 11 , wherein said indirect impulse pallet-stone comprises ruby or sapphire.

13. The horological detent escapement according to claim 1 , wherein the escapement is a direct impulse escapement, the escapement wheel transmitting the direct impulse directly to the balance.

14. The horological detent escapement according to claim 13 , wherein the escapement is a Robin-type escapement.

15. A horological movement comprising a train, wherein said horological movement also comprises the energy source, the regulating organ and the horological detent escapement according to claim 1 .

16. A timepiece, comprising the horological detent escapement according to claim 1 or the horological movement according to claim 11 .

17. A timepiece according to claim 16 , wherein the timepiece is a chronograph watch or split-time counter watch.

18. The horological detent escapement according to claim 4 , wherein said indirect impulse transmitter comprises an indirect impulse pallet-stone situated substantially close to a pivoting axis of said second mobile body and said pallets, said indirect impulse pallet-stone being situated on the first half, adjacent to said pivoting axis, of an arm of the pallets carrying an exit lock pallet-stone.