Abstract: A device for leakproofing instrument-control buttons, particularly for the winding and time-setting buttons (3) of watches, comprises a sealing element (8) fitted on the casing of the instrument in order to form a leaktight seal against the button, as well as a bridge unit (7) beneath which the button projects laterally and which carries an articulated lever (1) having a cam appendage (2) for pressing the button against the sealing element in a first position and for releasing the button to permit conventional movements thereof in a second position, the upper portion of the button (3) being machined in a manner such that a compartment is formed therein for housing a small piston element (4) in an axially slidable manner, the cam appendage (2) of the articulated lever (1) acting on the piston element (4), which is urged axially outwardly by resilient means (5) so as to take up clearance created between the button (3) and the casing.

Abstract: A device for locking the rotatable bezel of a watch and for rendering the winding button thereof watertight comprises a plastic washer connected to a flat surface of said button, coaxially thereto, so as to engage with circumferential knurling of the rotatable bezel, when the button is in a returned position, adjacent to the casing of the watch, in order to ensure the locking of the bezel. The device further comprises a seal which is carried by the button so as to be compressed between it and the casing when the button is in said returned position, in order to ensure watertightness of the button. Pressure means, movably supported by the casing, in a first position axially press the button holding it in said returned position and, in a second position, permits the outwards movement of the button to a rewinding and resetting position.