Timepiece with a cover provided with a hinge with an indexing mechanism

The indexing mechanism in the hinge addresses the instability of conical pin hinges by enabling stable, multiple angular positions and secure locking, enhancing the robustness and usability of watches with additional features.

WO2026126029A1PCT designated stage Publication Date: 2026-06-18DE LA MFG DHORLOGERIE AUDEMARS PIGUET & CIE

Patent Information

Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
DE LA MFG DHORLOGERIE AUDEMARS PIGUET & CIE
Filing Date
2025-12-05
Publication Date
2026-06-18

AI Technical Summary

Technical Problem

Conical pin hinges in pocket watches are prone to wear and instability due to excessive stress from heavy covers, leading to fragility and inability to maintain stable angular positions, especially in watches with additional features or complications.

Method used

A hinge with an indexing mechanism featuring two parts with indexing and counter-pieces, constrained by a compression spring, allowing for stable angular positioning and secure locking at multiple indexed positions, using teeth engagement and translational movement along a pivot axis.

🎯Benefits of technology

The hinge provides robust and stable angular positioning of the cover relative to the watch case, preventing wear and ensuring precise, stable visibility of horological functions, while allowing easy handling and reduced unintentional dislodging.

✦ Generated by Eureka AI based on patent content.

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Abstract

The invention relates to a timepiece (100) comprising a case (110), a cover (120) and a hinge (10) with an indexing mechanism. The hinge comprises a first part (20) and a second part (40) pivotably mounted on the first part (20). The latter comprises a wing (22), a support (26) and at least one indexing component (56a, 56b) mounted on the support (26) and provided with a face-gear toothing (64) defining a plurality of angular indexing positions. The face-gear toothing (64) is oriented in a general plane orthogonal to the pivot axis of the hinge. The second part (40) comprises a wing (42), a support (46a, 46b) and at least one counter-component (66a, 66b) mounted on the support (46a, 46b) and provided with a face-gear toothing (74) arranged to cooperate with the face-gear toothing (64) of the at least one indexing component. One of either the indexing component (56a, 56b) or the counter-component (66a, 66b) is mounted so as to be able to move in translation along the pivot axis of the hinge. The latter further comprises at least one stressing member (52) arranged to be able to move one of either the indexing component (56a, 56b) or the counter-component (66a, 66b) so that their respective face-gear toothings (64, 74) can either be engaged, under the stress of the stressing member (52), or spaced apart, against the action of the stressing member (52), so as to allow one of either the case (110) or the cover (120) to be moved angularly from one angular indexing position to another.
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Description

A clockwork component with a lid and a hinged indexing mechanism. technical field

[0001] The present invention relates to a timepiece with a cover and a hinge incorporating an indexing mechanism. The timepiece may, in particular, comprise a main case containing a basic watch movement and a secondary case acting as a cover and containing at least one horological function or indication. The hinge is unique in that it includes an indexing mechanism offering various indexed positions of the secondary case relative to the main case. State of the art

[0002] Pocket watches often include models with a flip-top cover. This cover protects the watch crystal from scratches, impacts, and dust. The cover is connected to the watch case by a hinge, allowing it to be opened and closed. Among the various hinges used in these pocket watches, those with a tapered pin are common.

[0003] Conical pin hinges, however, have several drawbacks, particularly regarding their robustness and the stability of the cover. These problems are especially noticeable in watches where the cover is made from solid materials, or when the cover is quite thick to accommodate, for example, one or more complications in timepieces with a multitude of features.

[0004] More specifically, when the lid is too heavy, the hinge is subjected to increased stress with each opening and closing. The extra weight puts excessive pressure on the tapered pin, thus increasing wear at the friction points between the pin and AUDEMA-40-PCT The hinge pins. Wear on the pin makes the hinge more fragile and prevents it from properly holding the lid, which could lead to play in the joint or, in the long term, a breakage of the hinge.

[0005] Furthermore, this type of hinge does not allow the cover to be held stably and precisely in different angular positions relative to the watch case. However, for timepieces whose cover is designed to house a mechanism that informs the user about a specific function, it is desirable to allow the user to adjust the cover's opening angle among several stable positions to obtain optimal visibility of the watch's function.

[0006] WO2023065867A1 discloses a wearable device comprising a main body, such as a smartwatch, and a wrist support connected to the main body by a dual-axis rotation mechanism, allowing for multidirectional orientation of the main body relative to the support. This allows the wearable device to adapt to various uses, such as video calls, taking photos, or listening to music.

[0007] However, this device does not include a hinge with an indexing mechanism. Brief summary of the invention

[0008] One aim of the present invention is therefore to provide a timepiece with a case connected to a cover by a hinge which is free from at least some of the aforementioned limitations.

[0009] More specifically, one aim of the present invention is to provide a watch part with a lid whose hinge connecting the lid to the case includes an indexing mechanism offering different indexed positions. AUDEMA-40-PCT

[0010] Another objective of the present invention is to provide a timepiece comprising a main case containing a basic watch movement and a secondary case acting as a cover and containing at least one horological function or indication. The hinge connecting the main case to the secondary case is of a robust design to allow for various stable indexed positions despite the weight of the secondary case.

[0011] According to the invention, these objectives are achieved, at least in part, by means of a timepiece comprising a case, a cover, and a hinge with an indexing mechanism. The hinge comprises two parts mounted pivoting relative to each other. The first part of the hinge includes a wing fixed to one of the case and the cover, a support, and at least one indexing piece mounted on the support and having front teeth defining a plurality of angular indexing positions. The front teeth are oriented in a plane orthogonal to the pivot axis of the hinge. The second part of the hinge includes a wing fixed to the other of the case and the cover, a support, and at least one counter-piece mounted on the support and having front teeth arranged to cooperate with the front teeth of said at least one indexing piece.One of the indexing pieces and the counter-piece is mounted to move translationally along the pivot axis of the hinge. The hinge further includes at least one constraint member arranged to move one of the indexing pieces and the counter-piece so that their respective front teeth can either be engaged under the constraint of the constraint member, or separated against the constraint member, to allow one of the housing and the cover to be moved angularly from one indexing angular position to another.

[0012] In one embodiment, the hinge comprises two pairs of front-toothed parts. Each pair includes an indexing part and a counter-part.

[0013] In one embodiment, the support for the first part of the hinge further comprises one or two recesses. The part or each AUDEMA-40-PCT the indexing document is arranged, at least in part, in the dwelling or one of the dwellings.

[0014] In one embodiment, the indexing part or parts comprise a body arranged in the housing or one of the housings of the support. The body and the housing are of complementary shapes and are configured to prevent any relative rotation between them.

[0015] According to one embodiment, the body of the part or each indexing part of the hinge has a shoulder intended to come against a wall of the housing when the part or each indexing part is in the unlocked position.

[0016] In one embodiment, the support for the second part of the hinge is in the form of two receptacles arranged on either side of the support for the first part of the hinge. The counter-pieces are arranged in this support.

[0017] According to one embodiment, each receptacle includes a housing that partially receives the indexing piece and the counter-piece.

[0018] According to one embodiment, the hinge further comprises at least one rod passing at least partially through the support of the first part of the hinge, through the indexing piece or each indexing piece and at least partially through the counter piece or each counter piece.

[0019] In one embodiment, the second part of the hinge comprises two side walls, each having a hole coaxial with the pivot axis of the hinge. Each counter-piece has a hub arranged in the hole of its respective wall so as to be driven into rotation about the pivot axis when the first and second parts of the hinge are pivoted relative to each other. AUDEMA-40-PCT

[0020] According to one embodiment, the hub of each counterpiece and the corresponding hole in the side wall are of complementary shapes and are configured so that each counterpiece can be mounted in a determined angular position in order to define the different positions of the plurality of indexed angular positions.

[0021] According to one embodiment, the constraining member of the hinge is arranged around the stem.

[0022] According to one embodiment, the counter-piece or one of the counter-pieces is fixed to the stem so that the pivoting of the housing relative to the cover causes the hinge stem to rotate around its axis.

[0023] In one embodiment, the indexing piece or each indexing piece has an internal housing in which a seal is fixed. The seal is mounted around the rod so that the rotation of the rod about its axis is dampened by the friction of the seal on the rod.

[0024] According to one embodiment, the profile of the front teeth of the indexing part or each indexing part is determined so that the angular pitch between the different positions of the plurality of indexed angular positions is constant and within a range of 10° to 30°.

[0025] According to one embodiment, the case is a main case containing a basic watch movement, while the cover is a secondary case containing at least one watch function or indication. Brief description of the figures

[0026] Examples of implementation of the invention are given in the description illustrated by the accompanying figures, in which: AUDEMA-40-PCT - Figure 1 illustrates a perspective view of a watch case comprising a secondary case hinged to a main case by a hinge, according to one embodiment; - Figure 2 illustrates a perspective view of the hinge of Figure 1; - Figure 3 illustrates an exploded view of the hinge of Figure 2; - Figure 4 illustrates an enlarged view of an indexing part from Figure 3; - Figure 5 illustrates an enlarged view of a counter-piece of Figure 3; - Figure 6 illustrates a top view of the hinge of Figure 2 in a closed configuration, - Figure 7 illustrates a cross-sectional view of the hinge of Figure 6 along AA, - Figure 8 illustrates a top view of the hinge of Figure 2 in an open configuration, and - Figure 9 illustrates a cross-sectional view of the hinge of figure 8 according to BB. Examples of embodiments of the invention

[0027] According to a preferred embodiment and with reference in particular to Figures 1 to 3, the timepiece 100 comprises a main case 110 containing a basic movement (not shown), a secondary case 120 containing a horological function, preferably a horological complication (not shown), and a hinge 10 connecting the main case 110 to the secondary case 120. The function or complication AUDEMA-40-PCT A horological device can include, in particular, a lunisolar calendar, a perpetual calendar, a moon phase display mechanism, or any other mechanism that provides the user with time information. It should be noted that such a mechanism does not necessarily require being coupled to a movement.

[0028] The hinge 10 comprises a first part 20 with a wing 22 fixed to the main housing 110 and a second part 40 with a wing 42 fixed to the secondary housing 110. With regard to figure 3, the wing 22, 42 of the first and second parts 20, 40 of the hinge has two fixing holes, preferably two counterbores 24, 44, for their fixing respectively to the main and secondary housing by means of screws.

[0029] The first part 20 of the hinge further comprises a central support 26 integral with the wing 22. The central support 26 includes a substantially cylindrical portion. This portion has a through hole 28 (Fig. 7) and two recesses 29 arranged on either side of the through hole. A rod 50 is partially arranged within the through hole 28. A constraint element 52, typically a compression spring, is arranged inside the through hole 28 around the rod 50, while two indexing pieces 56a, 56b are arranged in their respective recesses 29 against the respective ends of the constraint element.

[0030] According to Figure 4, each indexing piece comprises a body 58 and a front toothing 64, typically metallic, situated in a plane substantially orthogonal to the pivot axis of the hinge, which corresponds to the longitudinal axis of the stem 50 in this embodiment. The body 58 is substantially cylindrical and has two diametrically opposed flats 60. Each indexing piece 56a, 56b also includes an axial hole 63 to support and guide the stem 50 around its axis of rotation when the timepiece is opened.

[0031] It should also be noted that a passage 62 runs completely through the body 58 at the level of the flats. This passage is intended to temporarily hold a pin during the assembly of the hinge, as will be seen later. The peripheral wall of the housing 29 is shaped AUDEMA-40-PCT complementary to that of the body 58 is thus comprised of two diametrically opposed flat surfaces against which are positioned the flats 60 of the body of the respective indexing piece 56a, 56b in order to allow a translational movement of the latter along the rod 50 while preventing its rotation around the axis of the rod 50. The body 58 of the indexing piece as well as the peripheral wall of the housing 29 may have other non-circular sections in order to block the indexing piece from rotating.

[0032] Referring again to Figure 3, the second part 40 comprises two receptacles 46a, 46b arranged on either side of the central support 26 of the first part 20. Two counter-pieces 66a, 66b are arranged in the respective receptacles. According to Figure 5, each counter-piece comprises a hub 68, a disc 75 integral with the hub 68, and a front toothed section 74, typically metallic. The front teeth 74 are arranged on one face of the disc 75 in a plane substantially orthogonal to the pivot axis of the hinge, in this case in a plane substantially orthogonal to the longitudinal axis of the rod 50 according to the present embodiment, in order to engage with the front teeth 64 of the corresponding indexing piece 56a, 56b under the action of the constraining member 52. Each counter piece 66a, 66b also has an axial hole 73 for the passage of the rod 50.

[0033] In one embodiment, one end of the rod 50 is driven into the axial hole 73 of the first counter-piece 66a, while the other end of the rod 50 is mounted freely for rotation in the axial hole 73 of the second counter-piece 66b to allow assembly of the hinge as described below. The diameter of the axial hole of the second counter-piece 66b is thus slightly larger than the diameter of the rod 50.

[0034] Like the body of the indexing parts, the hub 68 of the counter-parts 66a, 66b is substantially cylindrical with two diametrically opposed flats 70. The two receptacles 46a, 46b each have a side wall 49 with a hole 48 into which the hub 68 of the respective counter-part is fixed, for example by pressing. Since the first counter-part 66a is integral with the rod 50, the latter is rotationally fixed to the second part 40 of the hinge. AUDEMA-40-PCT

[0035] The hole 48 in the side wall 49 of each receptacle 46a, 46b has two diametrically opposed flat surfaces arranged to correspond with the flats 70 of the hub 68. This allows the counter-pieces 66a, 66b to be angularly positioned so that the angular pitches of their front teeth 74 are positioned according to a reference, in particular so that the teeth of the counter-pieces mesh with those of the corresponding indexing pieces when the main inner surfaces of the housings 110, 120 are closest to each other. The various indexed positions can thus be chosen according to the angular orientation of the counter-pieces to correspond to the desired opening angles of the secondary housing 120 relative to the main housing 110, as will be seen later.

[0036] According to Figure 7, the ends of the compression spring 52 constrain the indexing pieces 56a, 56b into an axial locking position in which their front teeth 64 mesh with the front teeth 74 of the counter pieces 66a, 66b, thus immobilizing the hinge 10 to prevent any relative pivoting between the first and second parts 20, 40. The housing 29 of each indexing piece 56a, 56b is dimensioned so that the annular wall 30 is recessed relative to an annular shoulder 61 of the body 58 of the indexing pieces 56a, 56b. This recess allows axial movement of the indexing pieces along the rod 50 into an unlocked position in which the shoulder 61 abuts against the wall 30.

[0037] Thus, the two indexing pieces 56a, 56b are moved into the unlocked position by the action of the front teeth 74 of the counter-pieces 66a, 66b against the front teeth 64 of the indexing pieces when the second part 40 is pivoted relative to the first part 20 around the axis of the stem 50 during the pivoting of the secondary case 120 relative to the main case 110 of the timepiece. Since the front teeth of the indexing pieces and counter-pieces are made of a hard material, the axial displacement of the indexing pieces is caused by the interaction of their respective front teeth during the opening / closing of the timepiece 100. AUDEMA-40-PCT

[0038] It should be noted that the properties of the constraint element 52 are chosen in order to find a fair balance between the stability of the secondary case 120 in any of the indexed positions relative to the main case 110 while allowing easy handling of the timepiece when opening and closing it.

[0039] The hinge 10 allows the secondary housing 120 to pivot relative to the main housing 110 through an angle greater than 90°, preferably within a range of 90° to 180°. The user can pivot the secondary housing relative to the main housing until the desired angle is reached, for example, around 120°. The indexing parts 56a, 56b are then returned to the locking position to immobilize the hinge in an indexed position.

[0040] It should be noted that the profile of the front teeth 64, 74 of the indexing pieces and counter-pieces is configured so that the force exerted on the two parts 20, 40 of the hinge 10 is relatively high enough to cause a relative pivoting between these two parts. This prevents the secondary case 120 from unintentionally dislodging itself from one of the indexed angular positions. The teeth have faces with a desired inclination to achieve a compromise between the stability of the secondary case 120 in each indexed angular position and the force required to open / close the timepiece.

[0041] Indeed, the greater this inclination, the greater the force required to induce a translational movement in the indexing parts in order to pivot the secondary housing 120 relative to the main housing 110. Conversely, the smaller this inclination, the less force is required to cause a translational movement of the indexing parts, which can affect the stability of the secondary housing in an indexed position. The inclination of the front teeth can vary depending on the properties of the constraint element, which also influence the stability of the indexed positions, as mentioned previously. AUDEMA-40-PCT

[0042] The number of indexed positions is determined by the profile of the front teeth of the indexing parts and counter-parts. The front teeth, as illustrated in Figure 4, have twelve teeth to allow an angular displacement of 30° between two indexed positions. Thus, the two flats 70 of the hub 68 of the counter-parts 66a, 66b allow these counter-parts to be positioned angularly so that the different indexed positions can lock the hinge when the secondary housing 120 is preferably at an angle of 90°, 120°, 150°, and 180° relative to the main housing 110. It goes without saying that the profile of the front teeth of the indexing parts and counter-parts can be modified to have a different angular pitch between two indexed positions, for example, an angular pitch of 15° instead of 30°, in order to offer a wider choice of indexed positions.

[0043] It will be noted from figures 7 to 9 that the front teeth of the indexing parts 56a, 56b are arranged in the receptacles 46a, 46b of the second part 20 of the hinge.

[0044] The hinge may optionally include a friction system to slow the opening of the timepiece 100. For this purpose, each indexing piece 56a, 56b has an internal housing 59 in which an O-ring 54a, 54b is fixed. Each O-ring is mounted on the stem 50. Thus, when the secondary case 120 is pivoted relative to the main case 110, the pivoting of the second part 40 of the hinge relative to the first part 20 causes the stem 50 to rotate around its axis. This rotation is slowed by the friction created by the O-rings 54a, 54b on the stem.

[0045] As shown in Figure 7, the roughly cylindrical portion of the support has two assembly holes at its base to allow for easy assembly of the hinge. The hinge is preferably assembled as follows.

[0046] The constraint member 52 is first positioned in the through hole 28 of the central support 26 of the first part 20 of the hinge. The two indexing pieces 56a, 56b are then mounted in their AUDEMA-40-PCT respective housing 29 and then temporarily held in their unlocking position by means of a pin inserted into the passage 62 of the body 58 of each indexing piece through the assembly holes 32. The ends of the pin are housed in two diametrically opposed cavities made at the level of the flat surfaces of the peripheral wall of the respective housing 29 in order to lock the indexing pieces in translation.

[0047] The counter-pieces 66a, 66b are then placed in the two receptacles 46a, 46b of the second part 40 of the hinge, and their respective hubs 68 are fixed, preferably by pressing, into the holes 48 located in the side walls 49 of the second part. This is then positioned relative to the first part 20 of the hinge 40 so that the two receptacles 46a, 46b are positioned on either side of the central support 26 of the first part, with the axial hole 73 of each counter-piece 66a, 66a located opposite the axial hole 63 of the respective indexing piece.

[0048] The two pins are then removed from the indexing pieces 56a, 56b through the assembly holes 32, which causes the axial displacement of the indexing pieces, under the action of the compression spring 52, until the front teeth 64 of each indexing piece are in contact with the front teeth 74 of the respective counter piece 66a, 66b. With regard to figures 3 to 5, the rod 50 is then successively threaded into the axial hole 73 of the second counter piece 66b, into the axial hole 63 of the second indexing piece 56b, into the through hole 28 of the central support 26 inside the compression spring 52, into the axial hole 63 of the first indexing piece 56a and finally the end of the rod 50 is driven into the axial hole of the first counter piece 66a.

[0049] Other embodiments of the invention, briefly described below, may be envisaged without departing from the scope of the invention as defined by the attached claims.

[0050] In one embodiment, the hinge may consist of only one indexing piece. This piece may be mounted on the first part of the hinge and arranged to cooperate with a counter-piece mounted on the second part of the hinge. This indexing piece AUDEMA-40-PCT The hinge can be mounted in a support attached to the first part and comprising a clamping element acting on the indexing piece so that the latter can be moved axially to allow the second part to be locked in different angular indexing positions relative to the first part, according to the same principle as the embodiment illustrated and described previously. The first and second parts of the hinge can be fixed together by various means, for example, by a rod, one end of which is attached to the counter-piece, while the other end is pivotally mounted in an opening provided in the support of the first part, and is axially locked.

[0051] According to another embodiment, the indexing piece, or each indexing piece in the case of a hinge comprising two indexing pieces similar to the preferred form described previously, can be mounted in a fixed translational manner, while the counter-piece or each counter-piece can be mounted to move in translation and to cooperate with a constraint member.

[0052] In another embodiment, the hinge may have structural features similar to the illustrated embodiment but without a stem. The indexing pieces and counter-pieces may thus lack an axial hole. In this case, the hinge has no friction system. However, care must be taken to adapt the dimensions of the pieces and counter-pieces so that they can be held securely enough to pivot around the hinge's pivot axis or to move along this axis without requiring a supporting stem.

[0053] This hinge can also be used for timepieces fitted with a conventional cover, i.e. a cover without a clockwork mechanism, unlike the preferred embodiment mentioned above. AUDEMA-40-PCT List of references Hinge 10 Part 1 20 Wing 22 24 fixing holes (e.g., countersunks) Central support 26 Hole through 28 29 Housing Units Wall 30 Assembly holes 32 Part Two 40 Wing 42 Mounting holes 44 (e.g., countersunks) Receptacles 46a, 46b 47 Housing Units Hole 48 Side wall 49 Stem 50 Elastic element 52 (e.g., compression spring) Joints 54a, 54b Indexing parts 56a, 56b Body 58 Internal accommodation 59 Flat 60 Shoulder 61 Passage 62 Axial hole 63 Frontal dentition 64 Counterparts 66a, 66b Hub 68 Flat 70 Axial hole 73 Frontal dentition 74 Disc 75 Watch part 100 Main unit 110 Secondary 120 box AUDEMA-40-PCT

Claims

Demands 1. A watch component (100) comprising a case (110), a cover (120), and a hinge (10), the hinge comprising: a first part (20) having a wing (22) integral with one of the case (110) and the cover (120) and a support (26), a second part (40) having a wing (42) integral with the other of the case (110) and the cover (120) and a support (46a, 46b), said first and second parts (20, 40) being adapted to allow relative pivoting of the case (110) and the cover (120) about a pivot axis, the hinge further comprising at least one constraint member (52), characterized in that the first part (20) further comprises at least one indexing piece (56a, 56b) mounted on the support (26) and equipped of a front toothing (64) defining a plurality of angular indexing positions, said front toothing (64) being oriented in a general plane orthogonal to the pivot axis of the hinge,the second part (40) further comprises at least one counter-piece (66a, 66b) mounted on the support (46a, 46b) and having a front toothing (74) arranged to cooperate with the front toothing (64) of said at least one indexing piece (56a, 56b), one of the indexing piece (56a, 56b) and of the counter-piece (66a, 66b) is mounted to be able to move in translation along said pivot axis, and the constraining member (52) is arranged to be able to move one of the indexing piece (56a, 56b) and of the counter-piece (66a, 66b) so that their respective front teeth (64, 74) can either be engaged under the constraint of the constraining member (52), or spread apart, against the constraining member (52), to allow one of the housing (110) and the cover (120) to be moved angularly from one angular indexing position to another.

2. Watch part (100) according to claim 1, the hinge (10) comprising two pairs of front toothed parts (64, 74), each pair comprising an indexing part (56a, 56b) and a counter part (66a, 66b). AUDEMA-40-PCT 3. A watch part (100) according to any one of the preceding claims, wherein the support (26) of the first part (20) of the hinge (10) further comprises one or two housings (29), the indexing part or each indexing part (56a, 56b) being arranged, at least in part, in the housing or one of the housings (29).

4. A watch part (100) according to claim 3, wherein the indexing part or each indexing part (56a, 56b) of the hinge (10) comprises a body (58) arranged in the housing or one of the housings (29) of the support (26), the body (58) and the housing (29) being of complementary shapes and configured to prevent any relative rotation between them.

5. A watch part (100) according to any one of claims 2 to 4, wherein the support of the second part (40) of the hinge (10) is in the form of two receptacles (46a, 46b) arranged on either side of the support (26) of the first part (20) of the hinge (10) and in which the counter-pieces (66a, 66b) are arranged.

6. A watch part (100) according to the preceding claim, in which each receptacle (46a, 46b) has a housing (47) receiving in part the indexing piece (56a, 56b) and the counter piece (66a, 66b).

7. A watch part (100) according to any one of the preceding claims, the hinge (10) further comprising at least one rod (50) passing at least partially through the support (26) of the first part (20) of the hinge, passing through the indexing part or each indexing part (56a, 56b) and at least partially through the counter-part or each counter-part (66a, 66b).

8. A watch part (100) according to claim 7, in which the second part (40) of the hinge (10) has two side walls (49) each having a hole (48) coaxial with said pivot axis, each counter-piece (66a, 66b) having a hub (68) arranged in the hole (48) of the respective wall (49) so as to be driven in rotation about said pivot axis when said second part (40) is pivoted relative to said first part (20). AUDEMA-40-PCT 9. A watch part (100) according to the preceding claim, wherein said hub (68) and said hole (48) are of complementary shapes and are configured so that each counter-part (66a, 66b) can be mounted in a determined angular position in order to define the different positions of said plurality of indexed angular positions.

10. A watch part (100) according to any one of claims 7 to 9, wherein the constraining member (52) of the hinge (10) is arranged around the stem (50).

11. A watch part (100) according to any one of claims 7 to 10, wherein the counter-part or one of the counter-parts (66a, 66b) is integral with the stem (50) so that the pivoting of the case (110) relative to the cover (120) causes the stem (50) of the hinge to rotate about its axis.

12. A watch part (100) according to the preceding claim, in which the indexing part or each indexing part (56a, 56b) of the hinge is provided with an internal housing (59) in which a seal (54a, 54b) is fixed, the seal being mounted around the rod (50) so that the rotation of the latter around its axis is braked by the friction of the seal (54a, 54b) on the rod (50).

13. A watch part (100) according to any one of the preceding claims, wherein the profile of the front teeth (64) of the part or of each indexing part (56a, 56b) of the hinge is determined so that the angular pitch between the different positions of said plurality of indexed angular positions is constant and within a range of 10° to 30°.

14. Timepiece (100) according to any one of the preceding claims, wherein the case is a main case (110) containing a basic timekeeping movement while the cover is a secondary case (120) containing at least one timekeeping function or indication. AUDEMA-40-PCT