Bridge for guiding a balance of a timepiece

Abstract

The invention relates to a guide element (1) for guiding the pivoting, about an axis (A), of a balance (91) of a timepiece (200), comprising: - a first guide bearing (2) not fitted with a damper, and - a first blank (3), in particular a first balance bridge or cock, the first blank (3) comprising: - at least a first fixing portion (31) for fixing to another blank (4), - a first receiving portion (32) for receiving the first guide bearing (2), and - at least a first flexible arm (33) mechanically connecting the first fixing portion (31) to the first receiving portion (32).

Description

[0001] DESCRIPTION

[0002] TITLE: Bridge for guiding a balance wheel of a timepiece.

[0003] Technical field of the invention

[0004] The invention relates to a guide element for pivotally guiding a balance wheel of a timepiece. The invention also relates to a timepiece module comprising such a guide element. The invention further relates to a timepiece movement comprising such a guide element or such a timepiece module. The invention finally relates to a timepiece comprising such a guide element or such a timepiece movement or such a timepiece module.

[0005] State of the prior art

[0006] In mechanical watch movements, a sprung balance oscillator is usually used. The balance is guided in pivoting around an axis by means of bearings mounted in a movement frame. Conventionally, a first bearing is mounted in a plate of the movement by means of a first shock absorber and a second bearing is mounted in a balance bridge by means of a second shock absorber. The shock absorbers provide flexibility to the assembly to prevent the balance shaft from being damaged when the movement is subjected to a shock, the balance wheel having a high inertia and the balance shaft having to have pivots of reduced dimensions to optimize the autonomy of the movement.

[0007] However, an architecture such as described above has the disadvantage of being bulky in the direction of the balance pivot axis, that is to say generally in the thickness of the watch movement. This is particularly disadvantageous for producing an extra-flat movement. Presentation of the invention

[0008] The aim of the invention is to provide a guide element which overcomes the drawbacks mentioned above and improves the guide elements known from the prior art. In particular, the invention provides a simple and space-saving guide element in the direction of the thickness of the watch movement.

[0009] Summary of the invention

[0010] According to the invention, an element allows the pivoting guidance, around an axis, of a balance wheel of a timepiece. The element comprises:

[0011] - a first guide bearing without shock absorber, and

[0012] - a first draft, in particular a first balance bridge or balance cock, the first draft comprising:

[0013] - at least a first portion of attachment to another blank,

[0014] - a first portion for receiving the first guide bearing, and

[0015] - at least one first flexible arm mechanically connecting the first fixing portion to the first receiving portion.

[0016] The at least one first arm may be configured and / or arranged so as to define a displacement stiffness of the first receiving portion of the order of 8 N / mm or less than 10 N / mm or less than 20 N / mm or less than 50 N / mm or less than 100 N / mm in the direction of the axis and / or the at least one first arm may be configured and / or arranged so that the first receiving portion may move by more than 0.05 mm or by approximately 0.1 mm in the direction of the axis.

[0017] The guide element may comprise several first flexible arms, in particular 2, 3 or 4 first flexible arms mechanically connecting the at least one first fixing portion to the first receiving portion. The first arm(s) may comprise an openwork geometry and / or the first arm(s) may extend substantially radially to the direction of the axis and / or each arm may comprise two parallel branches extending from the first fixing portion(s) and approaching each other near the first receiving portion of the guide bearing.

[0018] The first fixing portion may have a rim shape and / or the first receiving portion of the first guide bearing may have a thickness of the order of 0.2 mm or less than 0.23 mm or less than 0.14 mm depending on the axis.

[0019] One of the at least one first arm may include a piton holder.

[0020] The first fixing portion may comprise a first portion for receiving a first guide bearing of an escapement wheel.

[0021] The guide element may include:

[0022] - a second guide bearing without shock absorber, and

[0023] - a second blank, in particular a second balance bridge or a plate, the second blank comprising:

[0024] - at least a second portion of attachment to the first draft,

[0025] - a second portion for receiving the second guide bearing, and

[0026] - at least one second flexible arm mechanically connecting the at least one second fixing portion to the second receiving portion.

[0027] The at least one second arm may be configured and / or arranged so as to define a displacement stiffness of the second receiving portion of the order of 8 N / mm or less than 10 N / mm or less than 20 N / mm or less than 50 N / mm or less than 100 N / mm in the direction of the axis and / or the at least one second arm may be configured and / or arranged so that the second receiving portion may move by more than 0.05 mm or by approximately 0.1 mm in the direction of the axis.

[0028] The guide element may comprise several second flexible arms, in particular 2, 3 or 4 second flexible arms, mechanically connecting the at least one second fixing portion to the second receiving portion.

[0029] The second arm(s) may comprise an openwork geometry and / or the second arm(s) may extend substantially radially in the direction of the axis and / or each arm may comprise two parallel branches extending from the second fixing portion(s) and approaching close to the second receiving portion of the guide bearing.

[0030] The second fixing portion may have a rim shape and / or the second receiving portion of the second guide bearing may have a thickness of the order of 0.2 mm or less than 0.23 mm or less than 0.14 mm depending on the axis.

[0031] One of the at least one second arm may include a piton holder.

[0032] The at least one second fixing portion may comprise a second portion for receiving a guide bearing of an escapement wheel and / or the at least one second fixing portion may comprise a second portion for receiving a guide bearing of an anchor.

[0033] According to the invention, a watch module comprises:

[0034] - a previously defined guide element, - a balance,

[0035] - an anchor, and

[0036] - an escapement mobile.

[0037] According to the invention, a watch movement comprises a watch module defined previously and / or a guide element defined previously.

[0038] According to the invention, a timepiece, in particular a wristwatch, comprises:

[0039] - a previously defined guide element, and / or

[0040] - a previously defined watch module, and / or

[0041] - a previously defined watch movement.

[0042] Presentation of figures

[0043] The objects, characteristics and advantages of the present invention are set forth in detail in the following description of a particular embodiment made without limitation in relation to the attached figures.

[0044] Figure 1 is a schematic view of an embodiment of a timepiece according to the invention, an embodiment of a timepiece module according to the invention being shown in detail in perspective.

[0045] Figure 2 is a perspective view of the embodiment of the watch module according to the invention, the module being assembled on a plate.

[0046] Detailed description

[0047] An embodiment of a timepiece 200 is described below in detail with reference to Figures 1 and 2. The timepiece 200 is for example a watch, in particular a wristwatch. The timepiece 200 comprises a watch movement 100, intended to be mounted in a timepiece case or box in order to protect it from the external environment. The watch movement 100 may be a mechanical movement, in particular an automatic movement.

[0048] Movement 100 includes:

[0049] - a 99 turntable, and

[0050] - a watch module 90, in particular an “escapement holder” module which is detailed below, the watch module 90 being attached or mounted on the plate. This mounting can be achieved using screws passing through holes 101 provided in the module and screwed into the plate 99.

[0051] The 90 watch module includes:

[0052] - an oscillator comprising a balance wheel 91 and a hairspring 92,

[0053] - an anchor 93, and

[0054] - an escapement wheel 94 comprising an escape wheel and an escape pinion, and

[0055] - a guide element 1 for guiding in pivoting, around an axis A, the balance 91.

[0056] Advantageously, in the watch module, the pivoting or rotational guidance of the balance wheel, the anchor and the escapement wheel are fully ensured.

[0057] The escapement wheel 94 also meshes with a finishing train of movement 100.

[0058] Guide element 1 includes:

[0059] - a first guide bearing 2 without shock absorber, and

[0060] - a first blank 3, in particular a first balance bridge 3 or balance cock as shown in the figures. The first bearing preferably comprises a pivot jewel 21 and a counter-pivot jewel 22. This first bearing is mounted, in particular driven, in a bore provided in the first blank. The first bearing, in particular the jewels mentioned above, is advantageously mounted directly in the first blank. No shock absorber is provided between the first bearing (or the jewels which compose it) and the first blank.

[0061] The first draft 3 includes:

[0062] - at least a first portion 31 for attachment to another blank 4,

[0063] - a first portion 32 for receiving the first guide bearing 2, and

[0064] - at least one first flexible arm 33 mechanically connecting the first fixing portion 31 to the first receiving portion 32.

[0065] The at least one first fixing portion advantageously has fixing means for fixing it to a second blank 4. These means may comprise through holes intended to receive screws screwed into the second blank 4.

[0066] In one variant, the first attachment portion may have a rim shape. In the variant shown, there are two first attachment portions:

[0067] - one of the first portions extending globally over approximately 120° around axis A, and

[0068] - one of the first portions extending only a few degrees around the A axis.

[0069] These first two portions of fixation can be seen as the same discontinuous portion of fixation.

[0070] Advantageously, the first fixing portion 31 may comprise a first portion 31 1 for receiving a first guide bearing 5 of the escapement wheel 94. The first guide bearing is for example a stone driven into a hole provided in the first portion 31 1 .

[0071] The first receiving portion 32 may have an annular shape surrounding the hole provided to receive the first bearing 2.

[0072] Preferably, the first portion 32 for receiving the first guide bearing 2 has a thickness of the order of 0.2 mm or less than 0.23 mm or less than 0.14 mm, this thickness being measured in the direction of the axis A, i.e. generally in the direction of the thickness of the movement.

[0073] The at least one first arm is preferably configured and / or arranged:

[0074] - so as to define a displacement rigidity of the first receiving portion of the order of 8 N / mm or less than 10 N / mm or less than 20 N / mm or less than 50 N / mm or less than 100 N / mm in the direction of the axis A of the guide bearing, and / or

[0075] - so that the first receiving portion can move by more than 0.05 mm or by approximately 0.1 mm in the direction of axis A. This movement can be limited by a watch case element, such as a crystal or a back, or by an element of the movement, such as the plate.

[0076] Preferably, the first arm(s) extend substantially radially in the direction of the axis A of the guide bearing.

[0077] To achieve such flexibility characteristics of the first blank, the first arm(s) comprise an openwork geometry. To achieve this openwork geometry, each arm may comprise two parallel branches 331 extending from the first fixing portion(s) 31. However, these branches approach each other near the first receiving portion 32 of the guide bearing 2. The branches are again parallel at the point where they join the first receiving portion 32 of the guide bearing 2. They are however separated by a narrow slot at this junction.

[0078] The geometric data of the arms are for example as follows:

[0079] - the height of the branches (measured parallel to direction A) is for example between 0.14 mm and 0.23 mm,

[0080] - the width of the branches (measured orthoradially to direction A) is for example between 0.24 mm and 0.25 mm,

[0081] - the distance between the branches (measured orthoradially to direction A) is for example between 1.4 mm and 1.7 mm,

[0082] - the width of the slot is for example of the order of 0.1 mm, for example 0.12 mm.

[0083] Preferably, as in the embodiment shown in Figures 1 and 2, the guide element 1 comprises:

[0084] - a second guide bearing 6 without a shock absorber, and

[0085] - a second rough sketch 4, in particular a second balance bridge or cock as shown in the figures.

[0086] The second bearing preferably comprises a pivot stone 61 and a counter-pivot stone 62. This second bearing is mounted, in particular driven, in a bore provided in the second blank 4. The second bearing, in particular the stones mentioned above, is advantageously mounted directly in the second blank. No shock absorber is provided between the second bearing (or the stones which compose it) and the second blank.

[0087] The second draft 4 includes:

[0088] - at least a second portion 41 for fixing to the first blank 3,

[0089] - a second portion 42 for receiving the second guide bearing 6, and

[0090] - at least one second flexible arm 43 mechanically connecting the second fixing portion 41 to the second receiving portion 42.

[0091] The at least one second fixing portion advantageously has fixing means for fixing it to the first blank 3. These means may comprise screw feet intended to receive the screws mentioned above. Alternatively, the assembly may be ensured by pins for positioning and by screws for fixing.

[0092] Preferably, as in the embodiment shown in the figures, the second attachment portion preferably has a rim shape. Alternatively, as in the first blank shown, there may be several second attachment portions. These different second attachment portions can be seen as a single discontinuous attachment portion.

[0093] Advantageously, the second fixing portion 41 may comprise a second portion 41 1 for receiving a second guide bearing 7 of the escapement wheel 94. The second guide bearing is for example a stone driven into a hole provided in the second portion 41 1.

[0094] The second receiving portion 42 may have an annular shape surrounding the hole provided to receive the second bearing 6.

[0095] Preferably, the second portion 42 for receiving the second guide bearing 6 has a thickness of the order of 0.2 mm or less than 0.23 mm or less than 0.14 mm, this thickness being measured in the direction of the axis A, i.e. generally in the direction of the thickness of the movement. The at least one second arm is preferably configured and / or arranged:

[0096] - so as to define a displacement rigidity of the second receiving portion of the order of 8 N / mm or less than 10 N / mm or less than 20 N / mm or less than 50 N / mm or less than 100 N / mm in the direction of the axis A of the guide bearing, and / or

[0097] - so that the second receiving portion can move by more than 0.05 mm or by approximately 0.1 mm in the direction of axis A. This movement can be limited by a watch case element, such as a crystal or a back, or by an element of the movement, such as the plate.

[0098] The displacement stiffness of the second receiving portion along the direction of axis A may be equal or substantially equal to the displacement stiffness of the first receiving portion along the direction of axis A. Alternatively, the displacement stiffness of the second receiving portion along the direction of axis A and the displacement stiffness of the first receiving portion along the direction of axis A may be different or substantially different. For example, the displacement stiffness of the second receiving portion along the direction of axis A may be of the order of three times or four times greater than the displacement stiffness of the first receiving portion along the direction of axis A.

[0099] Preferably, the second arm(s) extend substantially radially in the direction of the axis A of the guide bearing.

[0100] To achieve such flexibility characteristics of the second blank, the second arm(s) comprise an openwork geometry. To achieve this openwork geometry, each arm may comprise two parallel branches 431 extending from the second attachment portion(s) 41. However, these branches approach each other near the second receiving portion 42 of the guide bearing 2. The branches are again parallel at the point where they join the second receiving portion 42 of the guide bearing 2. They are however separated by a narrow slot at this junction.

[0101] The geometric data of the arms are for example as follows:

[0102] - the height of the branches (measured parallel to direction A) is for example between 0.18 mm and 0.23 mm,

[0103] - the width of the branches (measured orthoradially to direction A) is for example between 0.14 mm and 0.2 mm,

[0104] - the distance between the branches (measured orthoradially to direction A) is for example between 1.3 mm and 1.8 mm,

[0105] - the width of the slot is for example of the order of 0.1 mm, for example 0.12 mm.

[0106] Advantageously, the second fixing portion 41 may comprise a second portion 412 for receiving a first guide bearing 8 of the anchor 93. The first guide bearing is for example a stone driven into a hole provided in the second portion 412. An anchor bridge 89 may be fixed to the second blank 4 in order to complete the guidance of the anchor 93. For this purpose, the anchor bridge 89 may comprise a bearing 9.

[0107] In the described embodiments or variants, the first blank comprises three arms and the second blank comprises three arms. However, regardless of the embodiment or variant:

[0108] - the first draft may preferably comprise one, two, three or four flexible arms 33, and / or

[0109] - the second blank may preferably comprise one, two, three or four flexible arms 43.

[0110] Generally, the numbers of arms on the first and second blanks may be different and arbitrary. Preferably, the number of arms on one and / or the other of the blanks is odd and / or the arms of no pair of arms of the same blank are aligned or oriented parallel.

[0111] Regardless of the embodiment or variant, the arms preferably have orthoradial sections (relative to axis A) which are wire-like or whose largest length to width ratio is less than 5 or 3 or 2.

[0112] In the embodiments or variants described, the first blank comprises, on a first arm, a stud holder 332. However, whatever the embodiment or variant: the stud holder can be located on the second blank or on the first blank. This advantageously depends on the side of the balance where the hairspring 92 is located.

[0113] In the described embodiments or variants, the first and second blanks are bridges. These bridges together form a guide cage. However, regardless of the embodiment or variant, the first blank or the second blank may be a plate.

[0114] In the described embodiments or variations, the first and second blanks comprise flexible arms. However, regardless of the embodiment or variation, only one of the blanks may be provided with flexible arms. For example, the other blank may have a guide bearing mounted in a damper.

[0115] In the embodiments or variants described, the first blank can be made, for example, from a hardenable austenitic superalloy based on cobalt (Phynox) or from copper beryllium (CuBe). In the embodiments or variants described, the second blank can be made, for example, from a hardenable austenitic superalloy based on cobalt (Phynox) or from copper beryllium (CuBe). Thanks to the solutions described above, it is possible to produce extra-flat watch movements while benefiting from a balance wheel guidance solution that is particularly compact.

[0116] As seen previously, the geometries of the arms ensure a certain flexibility in the guidance of the balance.

Claims

DEMANDS 1. A guiding element (1) for pivoting, around an axis (A), a balance wheel (91) of a timepiece (200), comprising: - a first guide bearing (2) without a shock absorber, and - a first rough draft (3), in particular a first balance bridge or cock, the first rough draft (3) comprising: - at least a first portion (31) of attachment to another blank (4), - a first receiving section (32) of the first guidance stage (2), and - at least one first flexible arm (33) mechanically linking the first fixing portion (31) to the first receiving portion (32).

2. A guide element according to the preceding claim, characterized in that at least one first arm is configured and / or arranged so as to define a displacement rigidity of the first receiving portion of the order of 8 N / mm or less than 10 N / mm or less than 20 N / mm or less than 50 N / mm or less than 100 N / mm along the direction of the axis (A) and / or in that at least one first arm is configured and / or arranged so that the first receiving portion can move more than 0.05 mm or about 0.1 mm along the direction of the axis (A).

3. A guiding element according to any one of the preceding claims, characterized in that the guiding element comprises several first flexible arms (33), in particular 2, 3 or 4 first arms (33) Flexible links mechanically connecting at least one first mounting portion (31) to the first receiving portion (32). A guide element according to any one of the preceding claims, characterized in that the first arm(s) comprise an openwork geometry and / or in that the first arm(s) extend substantially radially in the direction of the axis (A) and / or in that each arm comprises two parallel branches (331) extending from the first mounting portion(s) (31) and approaching each other near the first receiving portion (32) of the guide bearing (2). A guide element according to any one of the preceding claims, characterized in that the first mounting portion has a rim shape and / or in that the first receiving portion (32) of the first guide bearing (2) has a thickness of approximately 0.2 mm or less than 0.23 mm or less than 0.14 mm along the axis (A).A guide element according to any one of the preceding claims, characterized in that one of at least one first arm comprises a stud holder (332). A guide element according to any one of the preceding claims, characterized in that the first fastening portion (31) comprises a first portion (311) for receiving a first guide bearing (5) of an escapement slide (94). A guide element according to any one of the preceding claims, characterized in that the guide element comprises: - a second guide bearing (6) without a shock absorber, and - a second draft (4), in particular a second bridge (4) of balance wheel or a plate, the second draft (4) comprising: - at least a second portion (41) for attachment to the first rough draft (3), - a second receiving section (42) of the second guidance (2) bearing (6), and - at least one second flexible arm (43) mechanically connecting the at least one second fastening portion (41) to the second portion (42) receiving element. Guide element according to the preceding claim, characterized in that at least one second arm is configured and / or arranged so as to define a displacement stiffness of the second receiving portion of the order of 8 N / mm² or less than 10 N / mm² or less than 20 N / mm² or less than 50 N / mm² or less than 100 N / mm² along the direction of axis (A) and / or in that at least one second arm is configured and / or arranged so that the second receiving portion can move more than 0.05 mm or approximately 0.1 mm along the direction of axis (A). Guide element according to any one of claims 8 and 9, characterized in that the guide element comprises several second arms (43) flexible, in particular 2, 3 or 4 second flexible arms (43), mechanically connecting at least one second fastening portion (41) to the second receiving portion (42). Guide element according to any one of claims 8 to 10, characterized in that the second arm(s) comprise an openwork geometry and / or in that the second arm(s) extend substantially radially in the direction of the axis (A) and / or in that each arm comprises two parallel branches (431) extending from the second mounting portion(s) (41) and approaching the second receiving portion (42) of the guide bearing (2). Guide element according to any one of claims 8 to 11, characterized in that the second mounting portion has a rim shape and / or in that the second receiving portion (42) of the second guide bearing (6) has a thickness of approximately 0.2 mm or less than 0.23 mm or less than 0.14 mm along axis (A). Guide element according to any one of claims 8 to 12, characterized in that at least one second arm comprises a stud holder.A guiding element according to any one of claims 8 to 13, characterized in that at least one second fixing portion (41) comprises a second portion (411) for receiving a guide bearing (7) of an escapement wheel (94) and / or in that at least one second fixing portion (41) comprises a second portion (412) for receiving a guide bearing (8) of an anchor (93). A watch module (90) comprising: - a guiding element (1) according to one of the preceding claims, - a pendulum (91), - an anchor (93), and - an escapement mechanism (94).

16. Watch movement (100) comprising a watch module according to the preceding claim and / or a guiding element according to any one of claims 1 to 14.

17. Timepiece (200), in particular a wristwatch (200), comprising: - a guiding element (1) according to any one of claims 1 to 14, and / or - a watch module (90) according to claim 15, and / or - a watch movement (100) according to the preceding claim.

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