Constant-energy escapement for timepiece

An escapement device for a mechanical timepiece including:

• an escapement wheel comprising teeth,
• a rocker,
• a mobile element,
• at least one piece forming part of an oscillator of the timepiece, such as a balance plate,
• the escapement wheel cooperating with the rocker and the mobile element,
• the rocker cooperating with the escapement wheel by blocking means and with the piece forming part of the oscillator by release means,
• the mobile element comprising elastic means arranged to store elastic energy, and cooperating with the escapement wheel by winding means and with the piece forming part of the oscillator by impulse means,
• characterized in that:
• the winding means are arranged to carry out a phase of winding the elastic means along a first direction of rotation of the balance and the impulse means are arranged to carry out an impulse phase given by the mobile element to the piece forming part of the oscillator during the rotation of the balance along at least a second direction of rotation of the balance,
• and in that:
• the impulse is given directly from the mobile element to the piece forming part of the oscillator.