Abstract: 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.

Abstract: A closing/opening system for a case of a timepiece is defined particularly in first and second parts of the case. The system includes a device for producing a mechanical connection, particularly a bayonet connection between these first and second parts and a device for creating a friction torque between these first and second parts. The device for creating a friction torque includes tightening faces to cooperate with one another when closing/opening the case and which are defined in the first and second parts. The system further includes a tightening element in one of these two tightening faces. The tightening element generates a constant friction torque during a course of travel of one of the two parts relative to the other when closing/opening the case of the timepiece.

Abstract: 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.

Abstract: Provided is a device for fastening a back on a middle portion of a watch. The back includes a cover arranged to form a bearing surface with the middle portion and a body arranged to rest in the middle portion. The device includes an indexing ring disposed between the back and the middle portion, and the ring includes at least one lower catch arranged to cooperate with the back and ensure the indexing with the back and an upper catch are arranged to cooperate with the middle portion and ensure the indexing of the back and ring assembly in relation to the middle portion, and the upper catch has a height greater than that of the lower catch, or vice versa.

Abstract: A device for fastening a back on a middle of a watch, the back having a shoulder forming a cover arranged to cover totally or partially with the middle and a body arranged to rest in the middle, the device including at least one pin integral with the middle and a gasket mounted between the back and the middle. The back includes, close to its periphery, at least one recess, the pin being arranged to slide in the recess between a first position, referred to as insertion position wherein the back is free, and a second position referred to as locking position wherein the back is locked and angularly positioned in relation to the middle. The recess includes at least one bump to form a hard spot and increase the torque during the passage of the pin at the bump.

Abstract: 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).

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A closing/opening system for a case of a timepiece is defined particularly in first and second parts of the case. The system includes a device for producing a mechanical connection, particularly a bayonet connection between these first and second parts and a device for creating a friction torque between these first and second parts. The device for creating a friction torque includes tightening faces to cooperate with one another when closing/opening the case and which are defined in the first and second parts. The system further includes a tightening element in one of these two tightening faces. The tightening element generates a constant friction torque during a course of travel of one of the two parts relative to the other when closing/opening the case of the timepiece.