Chronograph mechanism and watch movement equipped with such chronograph mechanism

Abstract

We provide watch movements equipped with a chronograph mechanism. [Solution] A chronograph mechanism 10 comprising a first counter wheel 21 fixed to a first zero reset mechanism 51 and a second counter wheel fixed to a second zero reset mechanism 52 and not on the same plane, comprising a first hammer 110 and a second hammer 120 configured on two levels and pivoting separately from each other, and an elastic coupling mechanism 116 positioned between them, comprising a first bracket 116.1 that presses the first support mechanism 111 and a second bracket 116.2 that presses the second support mechanism 112, wherein the first hammer is rotatably coupled to the second hammer when the rigidity of the elastic coupling mechanism prevents a stress greater than a predetermined amount from being applied to the second hammer.

Description

Technical Field

[0001] The present invention relates to a chronograph mechanism for a watch movement.

[0002] More specifically, the present invention relates to a chronograph mechanism provided with a mechanism for zero-resetting a chronograph counter.

[0003] The present invention also relates to a timepiece provided with such a chronograph mechanism.

Background Art

[0004] A chronograph mechanism enables on-demand measurement of time using a plurality of chronograph counters, such as minutes and seconds.

[0005] A chronograph mechanism typically includes a zero-reset mechanism for resetting the chronograph counter, thereby returning the chronograph counter to a reference position so that time can be measured on-demand again.

[0006] Conventionally, such a zero-reset mechanism consists of a zero-reset control unit that can be operated by a user via a button or an operating pusher stud accessible from the outside of an intermediate part to which a watch movement is attached.

[0007] The zero-reset control unit engages directly or indirectly with one or more zero-reset hammers that strike a zero-reset cam held by various chronograph counters via a lever.

[0008] The chronograph counter and the corresponding hand are reset to zero when the hammer presses the reset cam, and generate a driving couple sufficient to change the position of the chronograph counter until the chronograph counter returns to a reference position determined by the shape of the hammer and the reset cam.

[0009] In existing chronograph mechanisms, the hammers are either formed from a single piece or consist of separate parts, fixed to one another by fastening means. In this case, they have a common operating control unit. Exemplary embodiments are described in particular in European Patent Application No. 2241945.

[0010] Setting the zero-reset mechanism is complex, time-consuming, and requires skilled craftsmanship. In fact, to set such a mechanism, the seconds hammer must be in contact with the seconds zero-reset cam in its reference position. Next, the pin on the minute hammer must be pushed down so that the minute zero-reset cam is also in its reference position. This operation is time-consuming and complex, and can only be performed by a professional watchmaker.

[0011] One solution to this cumbersome setting operation is to use two overlapping hammers. These two overlapping hammers are conjugate in their angular motion, while allowing for a limited relative angular motion of one hammer relative to the other during zero reset. Such a solution is described in particular in Swiss Patent No. 220536. In particular, this approach allows both hammers to act simultaneously on their respective heart pieces, which helps prevent the chronograph hands from lagging behind at the reference position.

[0012] However, in such a solution, most of the operating energy is absorbed by the return and damper springs, which increasingly exerts resistance stress on the hammer's movement, so that the overlapping hammers contact the zero-reset cam with almost no energy. Therefore, there is a risk that the chronograph counter will not be set to zero precisely in such a mechanism.

[0013] Therefore, an improved chronograph mechanism is needed, in particular a zero-reset mechanism for the counters on such a chronograph mechanism. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] European Patent Application No. 2241945 [Patent Document 2] Swiss Patent No. 220536 [Overview of the project] [Problems that the invention aims to solve]

[0015] For this purpose, the present invention aims to provide a chronograph mechanism that provides a solution to at least one of the aforementioned problems.

[0016] One of the objectives of the present invention is to provide a zero-reset mechanism that provides accurate zero-reset for various chronograph counters.

[0017] One of the objectives of the present invention is to provide a highly reliable and stable zero-reset mechanism.

[0018] One of the objectives of the present invention is to provide a solution that makes it easier to assemble a set of several overlapping hammers that are rotatably coupled. [Means for solving the problem]

[0019] For this purpose, the present invention provides a chronograph mechanism for a watch movement comprising a first chronograph counter wheel fixed to a first zero-reset mechanism, and a second chronograph counter wheel fixed to a second zero-reset mechanism and not coplanar with the first zero-reset mechanism, wherein the chronograph mechanism is A first hammer and a second hammer configured to engage with a first zero-reset mechanism and a second zero-reset mechanism, respectively, and the first hammer and the second hammer pivot independently of each other. An elastic coupling mechanism disposed between a first hammer and a second hammer, comprising a first bracket pressing the first hammer and a second bracket pressing the second hammer so as to elastically restrain the second hammer with respect to the first hammer, whereby the first hammer is rotatably coupled to the second hammer when there is no stress applied to the second hammer that is greater than a predetermined value by the rigidity of the elastic coupling mechanism. It relates to a chronograph mechanism provided with a zero reset mechanism.

[0020] Such a zero reset mechanism ensures that the chronograph counters are completely zero reset to their reference positions.

[0021] In this type of architecture, the rotational coupling between the two hammers is guaranteed regardless of the angular positions of the hammers and the zero reset control unit because the coupling force between the two hammers does not depend on the angular movement of the zero reset control unit.

[0022] In addition to the features described in the previous paragraph, the chronograph mechanism according to the invention can have one or more complementary features from the following, taken individually or in any technically possible combination. A rotatable eccentric mechanism held by one of the hammers and configured to engage with one of the brackets on the elastic coupling mechanism by changing its angular position. The eccentric mechanism is held by the first hammer, has a first angular position configured to engage with the second bracket on the elastic coupling mechanism and elastically restrain the elastic coupling mechanism so as to release the pressure on the second bracket on the second hammer. The eccentric mechanism has a second angular position at a distance from the elastic coupling mechanism such that the second bracket presses a support mechanism on the second hammer. The first angular position of the eccentric mechanism is an assembly position and the second angular position of the eccentric mechanism is an operating position. The eccentric mechanism is held by the second hammer, and the eccentric mechanism engages with the second bracket on the elastic coupling mechanism and is configured to elastically restrain the elastic coupling mechanism such that the second bracket presses the eccentric mechanism, having a first angular position. The eccentric mechanism has a second angular position at a distance from the elastic coupling mechanism such that the eccentric mechanism presses a support mechanism in which the second bracket is held by the first hammer. The first angular position of the eccentric mechanism is the operating position, and the second angular position of the eccentric mechanism is the assembly position. One of the two hammers includes a stop mechanism that engages with a support surface on the other hammer when a stress greater than a predetermined value by the rigidity of the elastic coupling mechanism is not applied to the second upper hammer. The chronograph mechanism includes a device for restricting the relative angular movement between the first hammer and the second hammer. The device for restricting the relative angular movement is composed of a prong fixed to the second hammer that engages with an opening formed in the body of the first hammer. The prong forms a second support mechanism on the second hammer. The zero reset mechanism includes a zero reset control unit that can be actuated by the user and is configured to rotate one of the two hammers. The zero reset mechanism includes a zero reset control unit that can be actuated by the user and is configured to rotate the first hammer. The first hammer includes a first pawl configured to strike a first zero reset mechanism, the second hammer includes a second pawl configured to strike a second zero reset mechanism, and the second pawl has an angular gain with respect to the first pawl. The first hammer and the second hammer have a common rotation axis. The chronograph mechanism includes at least one position indicator arranged on one of the two hammers to indicate a specific angular position of the eccentric mechanism.

[0023] Another aspect of the present invention relates to a watch movement equipped with a chronograph mechanism according to the present invention.

[0024] Another aspect of the present invention relates to a timepiece equipped with such a watch movement according to the present invention, which comprises a chronograph mechanism according to the present invention.

[0025] The timekeeping device is preferably a wristwatch comprising a watch case configured to receive and incorporate a watch movement according to the present invention.

[0026] The object, advantages, and features of the present invention will become apparent from the following detailed description with reference to the following drawings. [Brief explanation of the drawing]

[0027] [Figure 1] This is a partial schematic diagram of an exemplary embodiment of the chronograph mechanism according to the present invention, located in a fixed position within a watch movement. [Figure 2] Figure 1 is a perspective view of the chronograph mechanism. [Figure 3] Figure 1 is an exploded view showing more specifically the first and second hammers, which overlap and are elastically coupled by an elastic coupling mechanism, on the chronograph mechanism according to the present invention. [Figure 4] This diagram shows the lower hammer on the chronograph mechanism, which features a pre-assembly mechanism, in more detail. [Modes for carrying out the invention]

[0028] In all drawings, common elements shall have the same reference numeral unless otherwise specified.

[0029] Figure 1 is a schematic top view of a portion of the chronograph mechanism 10 incorporated into the watch movement 1 according to the present invention.

[0030] Figure 2 shows a perspective view of the chronograph mechanism 10 shown in Figure 1.

[0031] Referring to Figures 1 and 2, the clock movement 1 comprises a plate 2 that serves as a support for various elements of the clock movement 1, in particular for a regulating gear train (not shown) for a time scale, which is driven by an energy source (not shown).

[0032] The chronograph mechanism 10 comprises a chronograph sequence 20, which can be kinematically coupled to a time sequence on demand via a coupling (not shown) controlled by a chronograph start / stop control unit.

[0033] For example, the coupling is a lever coupling that allows the coupling wheel to pivot. Other modified embodiments of couplings known to those skilled in the art can also be applied.

[0034] In particular, the chronograph row 20 comprises a first chronograph counter having a first chronograph counter wheel 21, for example, a seconds counter wheel, and a second chronograph counter having a second chronograph counter wheel 22, for example, a minutes counter wheel.

[0035] The first seconds counter wheel 21 is coupled to a first arbor 213, called a seconds counter arbor, which drives the seconds hand on a chronograph (not shown). The first arbor 213 also holds a first zero-reset mechanism 51, which is rotatably fixed to the arbor 213.

[0036] The second minute counter wheel 22 is coupled to a second arbor 223, called a minute counter arbor, which drives the minute hand of the chronograph (not shown). The second arbor 223 also holds a second zero-reset mechanism 52, which is rotatably fixed to the arbor 223.

[0037] The first arbor 213 and the second arbor 223 are coaxial.

[0038] The first wheel of the second counter 21 and the second wheel of the minute counter 22 overlap, are located in two separate planes, and are parallel to each other. The respective zero-reset mechanisms 51 and 52 also overlap each other.

[0039] The zero reset mechanisms 51 and 52 are, for example, snail-shaped, heart-shaped, or other zero reset cams, whose shape allows the zero reset mechanism to return to the reference position of the needle when actuated by the zero reset hammer.

[0040] In the illustrated example, the zero-reset mechanisms 51 and 52 are zero-reset heart pieces.

[0041] As shown in the diagram, the chronograph column 20 may also include a third additional counter, such as a time counter, which has a third chronograph counter wheel 23 connected to a third zero-reset mechanism 53.

[0042] The chronograph column 20 may include intermediate chronograph movable parts to obtain a desired ratio between the various counter wheels 21, 22, and 23 on the chronograph mechanism 10.

[0043] The chronograph mechanism 10 also includes a zero reset mechanism 100 for resetting various chronograph counters and returning the zero reset mechanisms 51, 52, 53 and the hands corresponding to these counters to their reference positions.

[0044] The zero-reset mechanism 100 comprises a first hammer 110 and a second hammer 120 that overlap each other and are shaped to engage with a first zero-reset mechanism 51 on the first chronograph counter and a second zero-reset mechanism 52 on the second chronograph counter, respectively. The hammers 110 and 120 are rotated by a zero-reset control unit 60, which can be operated by the user, for example, via a button or an actuation brumstud 61.

[0045] The zero reset control unit 60 is rotatable around the rotation axis 66 and engages directly or indirectly with one of the hammers 110, 120.

[0046] In the illustrated exemplary embodiment, the zero-reset control unit 60 directly engages with a first hammer 110 located in a lower position (i.e., a hammer near plate 2). However, the zero-reset control unit 60 can also directly engage with a second hammer 120 located in an upper position (i.e., a distal hammer on plate 2).

[0047] For this purpose, the first hammer 110 includes an actuation part 113, such as a pin or prong, which is securely mounted on the body of the first hammer 110 so as to protrude and is configured to directly contact and engage with a part of the zero reset control unit 60.

[0048] Figure 3 shows a more detailed exploded view of the set of overlapping hammers 110 and 120 according to the present invention.

[0049] The first hammer 110 and the second hammer 120 are assembled to pivot independently of each other around a common axis of rotation 105. According to a modified embodiment, the first hammer 110 and the second hammer 120 may have different axes of rotation that are parallel to each other.

[0050] The second hammer 120 has limited angular degrees of freedom relative to the first hammer 110. For this purpose, a device for limiting angular motion is placed between the first hammer 110 and the second hammer 120 to limit the angular movement of the second hammer 120 relative to the first hammer 110.

[0051] For example, a device for limiting relative angular motion is formed by a prong 112 fixed to one of the two hammers 110, 120, for example, the second hammer 120, and engages with an opening 117 formed in the body of the other hammer 110, 120, for example, the first hammer 110, thereby limiting the relative angular motion between the two hammers 120, 110.

[0052] As can be seen in Figure 4, the opening 117, which shows the first hammer 120 in more detail, is oval or arc-shaped, for example, to allow limited relative angular motion between the two hammers 110, 120 around the axis of rotation 105.

[0053] The elastic coupling mechanism 116 is positioned between the first hammer 110 and the second hammer 120, forming an elastic coupling between the two hammers 110 and 120.

[0054] More specifically, the elastic coupling mechanism 116 allows the first hammer 110 and the second hammer 120 to be rotatably coupled, while enabling the aforementioned relative angular degrees of freedom of the second hammer 120, due to the elastic strain of the elastic coupling mechanism 116 when a stress greater than a predetermined value defined by the rigidity of the elastic coupling mechanism 116 is applied to the second hammer 120.

[0055] More specifically, the elastic coupling mechanism 116 includes a first elastic bracket 116.1 that presses against the first support mechanism 111 on the first hammer 110, and a second elastic bracket 116.2 that presses against the second support mechanism on the second hammer 120.

[0056] The two elastic brackets 116.1 and 116.2 are joined on an elbow-shaped central body 116.3. The elastic coupling mechanism 116 is, for example, a spring, a leaf spring, a string spring, etc.

[0057] In the illustrated exemplary embodiment, the second support mechanism of the second hammer is formed by the prongs 112 of the second hammer 120. However, a second support mechanism separate from the prongs 112 may be provided.

[0058] The second support mechanism and / or prong 112 may be an additional element, or an element made from the same material as the body of the second hammer 120.

[0059] The elastic coupling mechanism 116 is configured to restrain the second hammer 120 from the first hammer 110 when a stress greater than a predetermined value is not applied to the second hammer 120 due to the rigidity of the elastic coupling mechanism 116, thereby rotatably coupling the second hammer 120 to the first hammer 110.

[0060] More specifically, the second hammer 120 is directed toward the first hammer 110 and includes a stop mechanism 122 configured to engage with a support surface 118 on the first hammer 110. Under the elastic constraint of the elastic coupling mechanism 116 that presses the two hammers 110, 120 together, the stop mechanism 122 of the second hammer 120 is maintained in a state pressed against the support surface 118 of the first hammer 110.

[0061] The first hammer 110 includes a first pane 115 configured to strike a first zero-reset mechanism 51 on a first counter. The second hammer 120 includes a second pane 126 configured to strike a second zero-reset mechanism 52 on a second counter.

[0062] When in a stationary position, that is, when no stress greater than a predetermined value with respect to the stiffness of the elastic coupling mechanism 116 is applied to the second hammer 120, the second pane 126 on the second hammer 120 is not aligned with the first pane 115 on the first hammer 110. In fact, the second pane 126 on the second hammer 120 is slightly offset forward (i.e., in the direction of the zero-reset mechanisms 51, 52) relative to the first pane 115 on the first hammer 110.

[0063] The forward offset of the second pane 126 on the second hammer 120 ensures that at the end of the movement of the hammers 110, 120 and the movement of the zero-reset control unit 60, both zero-reset mechanisms 51, 52 return to their reference positions. In fact, when the hammers 110, 120 are actuated, and the second zero-reset mechanism 52 on the second counter is in the zero-reset position, the supplemental angular displacement of the hammers 110, 120 generates a stress in the second pane 126 on the second hammer 120 that is greater than the stiffness of the elastic coupling mechanism 116, thereby allowing the first zero-reset mechanism 51 on the first counter to complete its zero-reset if it has not yet reached its reference position. The retrograde motion of the second hammer 120 relative to the first hammer 110 is thus initiated by counteracting the elastic stress of the elastic coupling mechanism 116.

[0064] The chronograph mechanism described below works as follows:

[0065] When the user presses the zero reset control unit 60 via the actuating bram stud 61, the zero reset control unit 60 pivots around its rotation axis 66, thereby engaging with the actuating part 113 on the first hammer 110, causing the first hammer 110 to pivot around the rotation axis 105.

[0066] When no stress is applied to the second pane 126 on the second hammer 120, the second hammer 120 is rotatably coupled to the first hammer 110 and is therefore also moved by the zero-reset control unit 60, pivoting around the rotation axis 105.

[0067] The two hammers 110 and 120 continue their angular motion under the action of the zero-reset control unit 60 until the pins 115 and 126 strike their respective zero-reset mechanisms 51 and 52.

[0068] As the second pin 126 advances on the second hammer 120, the second zero-reset mechanism 52 is reset to its reference position before the zero-reset control unit 60 reaches its full angular movement.

[0069] As the zero reset control unit 60 continues its angular displacement, the second zero reset mechanism 52 on the second counter, which is in a reference position which is a stationary position, exerts a stress on the second pane 126 that is greater than the stiffness of the elastic coupling mechanism 116. This stress elastically deforms the elastic coupling mechanism 116, changing the relative positions of the two hammers 110 and 120. This separation of the two hammers 110 and 120 allows the first hammer 110 to continue its angular motion driven by the zero reset control unit 60, ensuring that the first zero reset mechanism 51 on the first counter is completely reset.

[0070] When the zero reset control unit 60 reaches the end of its movement, the two panes 116 and 126 are aligned with each other, and the two zero reset mechanisms 51 and 52 are positioned at their reference positions.

[0071] The second hammer 120 further comprises a third pane 127 configured to reset the third zero-reset mechanism 53 to its reference position.

[0072] According to the present invention, the zero-reset mechanism 100 advantageously includes an eccentric mechanism 200 that facilitates the assembly of an elastic coupling mechanism 116 between two hammers 110 and 120. Such a pre-assembly mechanism 200 also allows the two hammers 110 and 120 to be pre-assembled before they are assembled into the watch movement 1.

[0073] According to the first modified embodiment shown in the figure, the eccentric mechanism 200 makes it possible to release the support contact between the elastic coupling mechanism 116 and one of the hammers 110, 120, in particular when assembling the two hammers 110, 120.

[0074] For example, the eccentric mechanism 200 is configured to release support contact between the elastic coupling mechanism 116 and the prong 112 of the second hammer 120, or to release support contact between the elastic coupling mechanism 116 and the second support surface support portion of the elastic coupling mechanism 116.

[0075] For this purpose, as shown in Figure 4, an eccentric mechanism, such as an eccentric clamping mechanism or eccentric screw, is held by, for example, a first hammer 110 and is rotatable around its axis of rotation. The eccentric mechanism has a body, which has an axis of rotation not at the center of the body.

[0076] For example, friction is provided between the eccentric mechanism 200 and the first hammer 110 to ensure that the eccentric mechanism is maintained in place.

[0077] The eccentric mechanism 200 has a first position called the assembled position, which is configured to engage with the second bracket 116.2 on the elastic coupling mechanism 116 and elastically restrain the elastic coupling mechanism 116 so as to be recessed relative to the prong 112. Thus, the eccentric mechanism 200 allows for pre-assembly that releases support from the second bracket 116.2 on the second hammer 120, more specifically, on the prong 112 in the exemplary embodiment described. This position is shown particularly clearly in Figure 4.

[0078] The eccentric mechanism 200 also includes a second position, called the operating position, shown by a dotted line in Figure 4, in which the eccentric mechanism 200 is separated from the elastic coupling mechanism 116, thereby allowing the second bracket 116.2 on the elastic coupling mechanism 116 to freely contact the second hammer 120 and, more specifically, the prong 112 in the exemplary embodiment described. This position of the elastic coupling mechanism 116 is also shown by a dotted line in Figure 4.

[0079] According to a second modified embodiment, the eccentric mechanism 200 is used to form an elastic coupling between two hammers 110, 120, which means that one of the brackets on the elastic coupling mechanism presses against the eccentric mechanism during operation.

[0080] For example, the eccentric mechanism 200 is held by the second hammer 120 and has a first angular position configured to engage with the second bracket 116.2 on the elastic coupling mechanism 116 so that the second bracket 116.2 presses against the eccentric mechanism 200, thereby elastically restraining the elastic coupling mechanism 116. The eccentric mechanism 200 has a second angular position where it is at a certain distance from the elastic coupling mechanism 116 so that the second bracket 116.2 presses against the support mechanism held by the first hammer 110. Thus, in this modified embodiment, the second position of the eccentric mechanism 200 that is not in contact with the elastic coupling mechanism 116 is the assembly position. This means that during assembly, the elastic coupling mechanism 116 is maintained in a pre-assembled state on one of the hammers between the two support members. When in use, the eccentric mechanism 200 is positioned in a first operational position to constrain the elastic coupling mechanism 116 and restore support for the second elastic bracket 116.2 in order to connect the two hammers.

[0081] The eccentric mechanism 200 has an impression that allows a tool to be inserted to facilitate its rotation.

[0082] Preferably, the mechanism includes at least one position indicator 128 positioned on one of the two hammers 110, 120 to indicate a first or second angular position of the eccentric mechanism 200. Preferably, the mechanism includes a first indicator indicating the assembly position and a second indicator indicating the operating position.

[0083] Conventionally, the zero reset control unit 60 engages with an elastic zero reset element (not shown) configured to return the zero reset control unit 60 to a neutral locked position between each user's operations.

[0084] The zero-reset mechanism 100 may also include a retaining mechanism (not shown) to fix the zero-reset mechanism 100 and ensure that the zero-reset control unit 60 is fully operational. The retaining mechanism is configured to temporarily hold the operation of the zero-reset control unit 60, and consequently the operation of the hammers 110 and 120, unless a specific stress is applied to the zero-reset control unit 60. Such a retaining mechanism is a safety mechanism to prevent unintended zero-reset of the hands of the chronograph mechanism 10. The retaining member exhibits dynamic behavior similar to that of a mechanical fuse.

[0085] As shown in various diagrams, the chronograph mechanism 10 includes a column wheel 63 for pressing the columns or controlling the various movements of various levers located between the two columns. The operation of a chronograph mechanism 10 having such a column wheel 63 is widely known, so there is no need to further explain the operation of such a wheel.

[0086] Of course, the chronograph mechanism 10 may be a cam-mounted chronograph mechanism that replaces the column wheel 63, without departing from the scope of the present invention.

[0087] The present invention also relates to a timekeeping device, such as a wristwatch, that incorporates such a clock movement. [Explanation of symbols]

[0088] 1. Watch movement 10 Chronograph Mechanism 51. First Zero Reset Mechanism 21 First chronograph counter wheel 21 52 Second Zero Reset Mechanism 22 Second chronograph counter wheel 110 The First Hammer 120 The Second Hammer 116 Elastic coupling mechanism 116.1 First bracket 116.2 Second bracket

Claims

1. A chronograph mechanism (10) for a watch movement (1) comprising a first chronograph counter wheel (21) fixed to a first zero-reset mechanism (51), and a second chronograph counter wheel (22) fixed to a second zero-reset mechanism (52) and not coplanar with the first zero-reset mechanism (51), wherein the chronograph mechanism (10) is A first hammer (110) and a second hammer (120) configured at two levels to engage with the first zero reset mechanism (51) and the second zero reset mechanism (52), respectively, the first hammer (110) and the second hammer (120) pivot independently of each other, An elastic coupling mechanism (116) disposed between the first hammer (110) and the second hammer (120), comprising: a first bracket (116.1) that presses the first hammer (110) so as to elastically restrain the second hammer (120) relative to the first hammer (110); and a second bracket (116.2) that presses the second hammer (120), wherein the first hammer (110) is rotatably coupled to the second hammer (120) when no stress greater than a predetermined value due to the rigidity of the elastic coupling mechanism (116) is applied to the second hammer (120); A chronograph mechanism (10) is provided with a zero-reset mechanism (100).

2. The chronograph mechanism (10) according to claim 1, characterized in that the zero reset mechanism (100) comprises a rotatable eccentric mechanism (200) which is held by one of the hammers (110, 120) and configured to engage with one of the brackets (116.1, 116.2) on the elastic coupling mechanism (116) by changing its angular position.

3. The chronograph mechanism (10) according to claim 2, wherein the eccentric mechanism (200) is held by the first hammer (110), and the eccentric mechanism (200) has a first angular position configured to engage with the second bracket (116.2) on the elastic coupling mechanism (116) and to elastically restrain the elastic coupling mechanism (116) so as to release pressure on the second hammer (120) against the second bracket (116.2).

4. The eccentric mechanism (200) is characterized in that it has a second angular position at a certain distance from the elastic coupling mechanism (116) such that the second bracket (116.2) presses against the support mechanism (112) on the second hammer (120), as described in claim 3, for the chronograph mechanism (10).

5. The chronograph mechanism (10) according to claim 4, characterized in that the first angular position of the eccentric mechanism (200) is an assembly position, and the second angular position of the eccentric mechanism (200) is an operating position.

6. The chronograph mechanism (10) according to claim 2, characterized in that the eccentric mechanism (200) is held by the second hammer (120), and the eccentric mechanism (200) has a first angular position configured to elastically restrain the elastic coupling mechanism (116) by engaging with the second bracket (116.2) on the elastic coupling mechanism (116) such that the second bracket (116.2) presses against the eccentric mechanism (200).

7. The chronograph mechanism (10) according to claim 6, characterized in that the eccentric mechanism (200) has a second angular position at a certain distance from the elastic coupling mechanism (116) such that the second bracket (116.2) presses against the support mechanism held by the first hammer (110).

8. The chronograph mechanism (10) according to claim 7, characterized in that the first angular position of the eccentric mechanism (200) is an operating position, and the second angular position of the eccentric mechanism (200) is an assembly position.

9. The chronograph mechanism (10) according to claim 1, characterized in that one of the two hammers (110, 120) is provided with a stopping mechanism (122) that engages with a support surface (118) on the other hammer (120, 110) when a stress greater than a value predetermined by the rigidity of the elastic coupling mechanism (116) is applied to the second hammer (120).

10. The chronograph mechanism (10) according to claim 4, further comprising a device for limiting the relative angular motion between the first hammer (110) and the second hammer (120).

11. The chronograph mechanism (10) according to claim 10, characterized in that the device for limiting the relative angular motion is formed by a prong fixed to the second hammer (120) that engages with an opening (117) formed in the body of the first hammer (110).

12. The chronograph mechanism (10) according to claim 11, characterized in that the prongs form the support mechanism (112) on the second hammer (120).

13. The chronograph mechanism (10) according to claim 1, wherein the zero-reset mechanism (100) comprises a zero-reset control unit (60) which can be operated by a user and configured to rotate one of the two hammers (110, 120).

14. The chronograph mechanism (10) according to claim 13, wherein the zero-reset mechanism (100) comprises a zero-reset control unit (60) which can be operated by a user and configured to rotate the first hammer (110).

15. The chronograph mechanism (10) according to claim 1, wherein the first hammer (110) comprises a first pane (115) configured to strike the first zero-reset mechanism (51), and the second hammer (120) comprises a second pane (126) configured to strike the second zero-reset mechanism (52), the second pane (126) having an angular gain relative to the first pane (115).

16. The chronograph mechanism (10) according to claim 1, characterized in that the first hammer (110) and the second hammer (120) have a common axis of rotation (105).

17. The chronograph mechanism (10) according to claim 2, further comprising at least one position indicator (128) positioned on one of the two hammers (110, 120) to indicate a specific angular position of the eccentric mechanism (200).

18. A watch movement (1) comprising the chronograph mechanism (10) described in claim 1.

19. A timekeeping device comprising the clock movement (1) described in claim 18.

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