A mechanical or electromechanical timepiece including a watch case delimiting an internal volume, the watch case including a back delimiting the watch case at the bottom; a crystal closing the watch case at the top, the crystal defining a useful display aperture; a middle part connecting the back and the crystal to one another; a horological movement housed in the internal volume of the watch case; at least one hand for displaying information visible via a useful display aperture and rotated with respect to the watch case by the horological movement with at least one driving belt extending at least partially in the useful display aperture, the timepiece includes the internal volume of the watch case filled with a fluid wherein at least one driving belt is submerged, and wherein the driving belt is made of a material wherein the optical refractive index is equal or substantially equal to that of the fluid.

A water-resistant watch case of a diving watch, includes at least one back mounted on a lower side of a middle part, and a crystal mounted with a fastening gasket on an upper side of the middle part. The back includes an annular bearing surface for coming into contact with an inner annular surface of the middle part of a shape complementary to the bearing surface during mounting of the back on the middle part. The annular bearing surface and the inner annular surface are inclined towards the inside of the watch case at a determined angle less than 90° relative to a central axis perpendicular to a plane of the watch case so as to distribute stresses between the back and the middle part due to the water pressure during a dive. The annular bearing surface and the inner annular surface are conical in shape.

A device is for fastening a back on a middle of a watch. The back has a shoulder forming a cover arranged to cover entirely partly with the middle and a body arranged to rest in the middle. The device includes at least one pin integral with the middle, a seal mounted between the back and the middle. The back includes, near its periphery, at least one groove, the pin being arranged to slide in the groove between a first position, called the insertion position in which the back is free, and a second position called locking position in which the back is locked and positioned angularly relative to the middle. The groove includes at least one bump to form a hard point and increase the torque when the pin passes through the bump.

Disclosed herein is an electronic device. The electronic device includes a housing provided to accommodate a printed circuit board, a cover coupled to the housing, and including a coupling protrusion protruding to a side of the housing to be accommodated in the housing, and including a coupling hole formed in the coupling protrusion, a fastening pin arranged in the coupling hole and configured to couple to the housing, and a sealing member arranged between an inner wall forming the coupling hole and the fastening pin to seal the coupling hole. Various other embodiments are possible.

A component mounting member including a base member which is provided with an attachment hole and attached to a case, an attachment member which is inserted into the attachment hole of the base member so as to be attached to an inner surface of the base member located on an inner side of the case, and a terminal which is provided on the attachment member and exposed from the inner surface of the base member and an outer surface opposite to the inner surface.

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 component is comprising an austenitic ferritic stainless steel, the austenitic ferritic stainless steel including a base portion composed of a ferrite phase, a surface layer composed of an austenitic phase, and a mixed layer formed between the base portion and the surface layer, the mixed layer being composed of the ferrite phase and the austenitic phase, in which the base portion contains Cr: 18 to 22 mass %, Mo: 1.3 to 2.8 mass %, Nb: 0.05 to 0.50 mass %, Cu: 0.1 to 0.8 mass %, Ni: less than 0.5 mass %, Mn: less than 0.8 mass %, Si: less than 0.5 mass %, P: less than 0.10 mass %, S: less than 0.05 mass %, N: less than 0.05 mass %, C: less than 0.05 mass %, and a balance being composed of Fe and inevitable impurities, in which the surface layer contains 1.0 to 1.6 mass % of nitrogen, in which the surface layer has, at a surface of the surface layer, an oxide film having a thickness of 2.5 nm or greater, as calculated in terms of oxygen profiles in AES analysis.

A sub-assembly of external parts including, a bolt interposed between a first component and a second component compressing together a joint, securing them together by axially blocking the first component, and which cooperates with the second component to enclose a ball occupying a well of depth greater than its diameter, that an orientation housing in the second component or the bolt includes, framed by channels of depth less than its diameter, limited by stops, which ball can occupy, when subjected to the gravity field and/or a magnetic field, both an orientation housing and a complementary housing of depth less than its diameter, that the bolt or respectively the second component includes, for their relative drive by the ball when it is simultaneously braced on a channel and a complementary housing.

A sub-assembly of external parts including, a bolt interposed between a first component and a second component compressing together a joint, securing them together by axially blocking the first component, and which cooperates with the second component to enclose a ball occupying a well of depth greater than its diameter, that an orientation housing in the second component or the bolt includes, framed by channels of depth less than its diameter, limited by stops, which ball can occupy, when subjected to the gravity field and/or a magnetic field, both an orientation housing and a complementary housing of depth less than its diameter, that the bolt or respectively the second component includes, for their relative drive by the ball when it is simultaneously braced on a channel and a complementary housing.

A device is for fastening a back on a middle of a watch. The back includes a cover arranged to form a bearing surface with the middle and a body arranged to rest in the middle. The device includes a ring disposed between the back and the middle, the ring being arranged to ensure the water resistance and indexing of the back. The ring includes an upper part ensuring the water resistance and a median part including positioning to ensure precise placement of the back.