the cam 22 reaches its upper position oblong holes 27 28 are provided in the middle 5 of the first case 2 then in the hinge element 13 a respectively allowing the passage of the first lever 23 the other end of the first lever 23 includes a finger 30 capable of circulating around the groove 19 provided in the tip 18 of the arbor 15 irrespective of the position of the first case 2 provided in the second case 3 is a second lever 32 pivotably mounted around an axis 32 a secured to the frame of the second part of the movement and constituting the second actuating means an oblong hole is provided in the middle 8 of the second case 3 another oblong hole 33 is provided opposite the hinge element 13 b allowing the passage of the second lever 32 at its end on the arbor 15 side the second lever 32 has a finger 34 capable of circulating around the groove 21 of the end 20 of the arbor 15 irrespective of the position of the second case 3 at its other end the second lever 32 has a beak 36 arranged to cooperate with a toothed date wheel 38 of the date module a return spring 40 is provided connecting the second lever 32 to the arbor 15 allowing the second lever 32 and the arbor 15 to return to their initial position when the cam.