Abstract: A timepiece includes a casing having a casing interior having a viewer's side provided with a viewing opening, a base side provided with a sound aperture, and an annular surface surrounding the sound aperture. A membrane extending over the sound aperture closes the base side of the casing interior, the membrane having a circumferential region in sealed connection with the annular surface. A tensioning device maintains the membrane at a desired tension in the radial direction. A vibration generator arranged in the casing interior produces a sound whose frequency can be adjusted by adjusting the tension of the membrane.

Abstract: A timepiece movement movement comprises a casing having a mechanical energy source, a work train driven by the energy source, a fixed wheel mounted on the casing, and a tourbillion comprising a cage which bears a balance wheel, an escape mobile provided with a pinion engaging with the fixed wheel, and a cage wheel rotationally joined to the cage and provided on its periphery with a toothing engaging with the work train. The casing of this movement is constituted, in its part occupied by the tourbillion, by a transparent material. In addition, the cage wheel comprises a transparent-material platelet, which extends radially beyond the other constituents of the tourbillion.

Abstract: A timepiece movement movement comprises a casing having a mechanical energy source, a work train driven by the energy source, a fixed wheel mounted on the casing, and a tourbillion comprising a cage which bears a balance wheel, an escape mobile provided with a pinion engaging with the fixed wheel, and a cage wheel rotationally joined to the cage and provided on its periphery with a toothing engaging with the work train. The casing of this movement is constituted, in its part occupied by the tourbillion, by a transparent material. In addition, the cage wheel comprises a transparent-material platelet, which extends radially beyond the other constituents of the tourbillion.