A back (1) for a watch case (50), the back (1) including a first element (10) arranged so as to be screwed onto the watch case (50), and a second element (20) including an end face bearing a pattern (M), the second element (20) being mounted such that it can move in rotation about an axis (C) passing through the centre of the case (50), wherein the second element (20) has a brake arranged so as to hold same relative to the first element (10) in different angular positions about the rotational axis (C), the brake being disposed between the first and second elements (10, 20).

A method for frequency tuning a set of plates of a watch. The plates are disposed one above the other forming a watch dial with a space defined between the plates. A mechanical shock to the set of plates is generated, and the vibration frequency of each plate is checked. The vibration frequency of at least one of the plates is matched if different from the other plate so as to obtain an identical vibration frequency for each plate in order to tune the plates at least according to the first vibration eigenmode so as to avoid any contact between the plates as a result of any mechanical shock.

Disclosed is a timepiece including a case, a movement and a vibration-generating device intended to produce a sound, the latter two accommodated in the case, a device for amplifying the vibrations from the vibration-generating device, and a membrane receiving the amplified vibrations and generating a sound to outside the timepiece. The vibration-amplifying device includes a lever pivotally mounted on a support in a pivoting plane non-parallel to the plane of the membrane and actuated by a transmission member cooperating with the vibration-generating device to transmit the vibrations to the lever, the lever being integral with the membrane at least translationally in the pivoting plane so a movement of the transmission member, generated by vibration of the transmission member linked to the vibration-generating device and transmitted to the membrane by way of the lever actuated by the transmission member, generates an amplified movement of the membrane for an amplified sound.

Disclosed is a mechanical wristwatch including a case having a middle, a back cover and a bezel, a vibration-generating device for generating vibrations which are intended to produce at least one sound, which is accommodated in the case, a vibration-amplifying for amplifying the vibrations generated by the vibration-generating device, and a membrane arranged to receive the amplified vibrations and generate a sound from the inside to the outside of the wristwatch. The vibration-generating device is a rotary element having a reading surface including at least one groove arranged to generate sounds. The wristwatch also includes a unit for rotationally driving the rotary element, an actuator for such unit, and a transmission member arranged to cooperate with the rotary element to transmit, to the vibration-amplifying device, the vibrations generated by the groove during rotational movement of the rotary element.

An arrangement for the holding and vibration transmission of an acoustic radiating membrane (10) in a striking or musical watch (1) case (2). The case includes at least one crystal (3) mounted on a middle (4) and a back (5) mounted on a side opposite the middle. The acoustic radiating membrane is held in a portion of the watch case, such as the middle by at least one connection part (12) disposed between a peripheral rim of the membrane or an edge element (11) of the membrane and the middle by acting for the holding of the membrane in a direction parallel to the plane of the watch. The connection part may be a screw screwed into a threaded opening (14) of the middle and coming into contact with the edge element of the membrane.

A striking watch is provided with an acoustic radiating membrane made of metallic material or amorphous metal. The membrane takes the form of a loop with walls of a certain thickness to be connected by a first edge portion to a middle part of a watch case and by a second edge portion to a bezel fixed to a watch crystal. The bezel connected to crystal is movable with respect to the case middle via the membrane during the vibration of membrane once a sound is generated by a watch striking mechanism in the watch case. The membrane is configured with a wall of a specific thickness in an active region dependent on the mass of the bezel connected to the crystal, to obtain a frequency f.sub.0 of a first vibration mode.

A fixation assembly is configured to fix an electroacoustic transducer to a shell of the electronic device, and includes a first support and a second support. The first support defines a receiving space and a sound transmission channel communicating with the receiving space. The electroacoustic transducer is received in the receiving space. The second support is engaged with the first support and configured to restrict freedom of the transducer assembly cooperatively with the first support. Even when the electronic device is under extreme conditions, a relative position between the electroacoustic transducer and the fixation assembly remain unchanged. The second support is engaged with the shell to fix the first support and the electroacoustic transducer with the shell, such that the electroacoustic transducer is fixed relative to the shell, improving reliability of the electronic device under extreme conditions.

A musical timepiece includes a gong fastened to a structure or a resonator of a watch case, the resonator rigidly assembled to the structure around a chamber, by lugs allowing vibration of the resonator within a determined frequency range, the chamber enclosing a sealing element forming with the lugs the only mechanical connection between the structure and the resonator. The structure or the resonator includes a groove receiving a gasket in contact with the structure and the resonator The structure structure or the resonator or the sealing element includes a rigid protruding relief portion compressing a gasket in its groove, with a hardness less than 20 Shore A, for minimum damping of the vibration of the resonator.

The striking or musical watch includes a watch case having a case middle and a back attached to the case middle in a sealed manner and in a detachable manner, a glass closing the case in a sealed manner, a watch movement or a watch electronic module retained in the interior of the watch case and equipped with a sonic vibration generator to be activated during specific periods in order to produce a sound or music. The watch includes at least one acoustic radiation membrane made at least in part of wood or a wood composite material and attached to a part of the case in order to radiate the sound produced by the sonic vibration generator towards the exterior of the case.

Disclosed is a timepiece including a case containing a movement, at least one device for generating vibrations intended to produce at least one sound, at least one device for amplifying the vibrations generated by the vibration-generating device, the device for amplifying the vibrations including a lever linked to a support by an articulation about a single axis of rotation and arranged to be actuated by a transmission member cooperating with the vibration-generating device to transmit the vibrations to the lever. The device for amplifying the vibrations includes at least one plate arranged to cooperate with the lever in order to be displaced according to a vibration movement, the plate being housed in the case so as to form a free space on the periphery of the plate over at least 70%, preferably at least 80%, of the perimeter of the plate.