A timepiece and a tool to separate a back from a middle, which jointly delimit a watch case of this timepiece, inside which a horological movement is housed, this tool having the appearance of a wedge, i.e. an acute-shaped part formed by a first face and a second face which intersect at an angle of less than 90 and which are connected to one another by a rounded portion, the first face of the tool being oriented such that it extends parallel to a mean plane wherein the horological movement is located when an horologist engages this tool between the back and the middle in order to separate this back from this middle, the rounded portion being connected to the second face by a curved portion, the curvature whereof is directed towards the inside of a surface delimited by the first and second faces.

A watch case (10) including a back (30) driven into a middle (20) by a joint (40), and including a body (31) from which radially extends a lip (32), the body (31) including an axial annular shoulder (310) and the lip (32) including a radial annular shoulder (320). The middle (20) has an axial opening (21), an axial annular shoulder (200), and a radial annular shoulder (201) resting against the radial annular shoulder of the lip, the joint being interposed between the axial annular shoulders. The axial annular shoulders have peripheral profiles of complementary shapes, substantially circular, including one and the other, a first circular-arc-shaped portion having a first radius (R1, R2), and a second circular-arc-shaped portion to which is connected the first portion, having a second radius (r1, r2) the value of which is lower than that of the first radius (R1, R2).

A waterproof structure for watch is provided, which includes a watch case, a watch cover, a bottom case, and a circuit module. The watch cover is fixedly provided on one side of the watch case, the bottom case is fixedly provided on the other side of the watch case, and the circuit module is provided within the watch case. A display screen is provided between the watch case and the watch cover, and a first sealing ring is provided between the watch cover and the display screen. The first sealing ring is fixedly provided on the watch cover and abuts against the display screen, rendering it difficult for moisture to enter an interior of the watch and damage the circuit module through a connection position between the watch cover and the display screen, thereby improving a connection sealing between the water cover and the display screen.

The water-resistant watch case includes at least one crystal mounted on an upper side of a middle, a fastening gasket positioned between an upper annular inner wall of the middle and an upper annular outer wall of the crystal. The crystal includes an annular peripheral surface below the upper annular outer wall inclined at an angle smaller than 90 in relation to an axis perpendicular to a plane of the watch case. The peripheral surface comes into contact against an annular inner surface of the middle inclined at an angle similar to the inclination of the annular peripheral surface and below the upper annular inner wall of the middle. The annular peripheral surface and/or the annular inner surface of the middle includes a domed contact portion for a contact on an annular contact line between the two surfaces.

The water-resistant watch case includes at least one crystal mounted on an upper side of a middle, a fastening gasket positioned between an upper annular inner wall of the middle and an upper annular outer wall of the crystal. The crystal includes an annular peripheral surface below the upper annular outer wall inclined at an angle smaller than 90 in relation to an axis perpendicular to a plane of the watch case. The peripheral surface comes into contact against an annular inner surface of the middle inclined at an angle similar to the inclination of the annular peripheral surface and below the upper annular inner wall of the middle. The annular peripheral surface and/or the annular inner surface of the middle includes a domed contact portion for a contact on an annular contact line between the two surfaces.

A device for fastening a back (1) to a middle (2) of a watch case (100), the back (1) being arranged to be driven onto the watch case (100). The device includes a casing ring (3) to which is connected at least one position pin (4), the position pin (4) being arranged to cooperate with at least one machining (10) in the back (1) so as to guarantee the orientation of the back (1) relative to the middle (2) along the 12 o'clock-6 o'clock axis of the watch.

A device for fastening a back (1) to a middle (2) of a watch case (100), the back (1) being arranged to be driven onto the watch case (100). The device includes a casing ring (3) to which is connected at least one position pin (4), the position pin (4) being arranged to cooperate with at least one machining (10) in the back (1) so as to guarantee the orientation of the back (1) relative to the middle (2) along the 12 o'clock-6 o'clock axis of the watch.

A method for manufacturing gasket seals by producing, through machining operations, a plurality of cuts in an assembly (10) produced by at least two identical joined tubes (20), each tube (20) extending along a longitudinal axis between two ends, the end of one tube (20), referred to as first end (21), having a shape complementary to the shape of the end of the other tube (20), referred to as second end (22), so that said first and second ends (21, 22) cooperate by complementarity of shape.

A water-resistant closing device for a watch case, the device including an annular gasket (1) arranged to be placed between a middle (2) and a back (3), a bezel or a crystal (4), or a bezel and a crystal, or a back and a crystal. The gasket (1) has on its middle portion a bulge (10) protruding on its outer lateral face (11), the bulge being arranged to be engaged against the middle (3) and compressed following the installation of the back or of the crystal on the middle, the bulge being delimited by an upper (12) and lower material countersink (13) on either side of the bulge (10) in the non-compressed state of the gasket (1) to facilitate its installation and its deformation.

A water-resistant closing device for a watch case, the device including an annular gasket (1) arranged to be placed between a middle (2) and a back (3), a bezel or a crystal (4), or a bezel and a crystal, or a back and a crystal. The gasket (1) has on its middle portion a bulge (10) protruding on its outer lateral face (11), the bulge being arranged to be engaged against the middle (3) and compressed following the installation of the back or of the crystal on the middle, the bulge being delimited by an upper (12) and lower material countersink (13) on either side of the bulge (10) in the non-compressed state of the gasket (1) to facilitate its installation and its deformation.