Shock-absorber for a pivot of an axle of a horological mobile element

Abstract

The present invention relates to a shock-absorbing bearing (1) for a pivot of a clockwork mechanism's axis comprising a flexible guide component (2) comprising a central rigid portion (20) in which at least one pivoting bearing (3, 4) is formed or fixed on or in which a pivot of the axis of a clockwork mechanism is pivoted, an outer rigid portion (21) intended to be driven or fixed in or on a fixed part of a clockwork movement comprising the mechanism and an elastic portion (22) connecting the central rigid portion (20) to the outer rigid portion (21) and arranged to allow radial and axial displacement of the central rigid portion (20) relative to the outer rigid portion (21) when it is deformed.The damper further includes a stop and centering member (5) mounted integrally with the outer rigid portion (21) of the flexible guide component (2) and comprising an opening (50) intended to receive the pivot of the axis of the clockwork mechanism and arranged to serve as a radial stop for said pivot and a first conical portion (52) arranged to cooperate with a corresponding second conical portion (201) of the central rigid portion (20) of the flexible guide component.

Description

[0001] The present invention relates to a damping bearing for a pivot of an axis of a clockwork mobile.

[0002] In a watch movement, a shock absorber or shock absorber bearing is an elastic bearing whose purpose is to absorb shocks received by the pivots of an axis of a watch wheel. Shock absorbers are particularly widely used for the pivots of the balance staff. A conventional bearing designed to support the pivots of the balance staff is composed of a jewel through which the pivot passes and a counter-jewel on which the pivot pivots. However, given the small diameter of the balance staff and the significant mass of the balance, with a simple conventional bearing, even small shocks could cause the pivot and / or the balance staff to break. Shock absorber bearings have therefore been developed to absorb shocks and prevent breakage of the balance staff pivots.

[0003] In a conventional shock absorber, the stone and counter-stone are subjected to the action of a spring, generally called a lyre because of its shape. In the event of an axial shock, the stones and in particular the counter-stone can lift slightly until the bearing surface of the pivot comes into contact with a fixed part of the shock absorber. To absorb lateral shocks and to recenter the pivot in the bearing (which is essential for the proper functioning of the mobile), the stone is fixed in a support equipped with an inclined plane (cone) which allows a small lateral displacement, limited by the pivot pin which comes into contact with a fixed part of the shock absorber. To make the system even more efficient, the support can include two inclined planes (double cone) which guarantee an even more effective repositioning / recentring of the pivot in the event of an impact, particularly in the event of a significant impact.These shock absorbers are known under various names: Incabloc, Pare-choc Kif, Shock-Resist, etc.

[0004] Although very efficient, conventional shock absorbers are very bulky in height: the combination of a spring, the two stones, their support, a fixed stop and one or two cones for centering makes the system very thick. This thickness is a disadvantage when you want to make a thin or extra-flat caliber.

[0005] Document US 4,143,511 describes a shock-absorbing bearing comprising a fixed part having an opening through which the pivot pin passes, a cap in which the pivot is pivoted and elastic arms connecting the cap to the fixed part. The cap comprises conical centering surfaces cooperating with the straight surface of the opening of the fixed part for repositioning / centering the pivot in the event of an impact.

[0006] Document CH1881071 describes a shock-absorbing bearing comprising a bearing body having a first opening for the passage of the pivot pin and a rim adjacent to the opening and characterized by a first frustoconical surface. The bearing further comprises an elastic pad formed in one piece and the central part of which comprises a second frustoconical surface intended to cooperate with the first frustoconical surface of the bearing body for repositioning and centering the pivot.

[0007] These two documents, although describing elastic bearings made from a single piece, preferably made of plastic, do not concern themselves with the overall thickness of the shock absorber bearing. Indeed, in these documents, the elastic element and the centering element occupy two separate levels, contributing to the height dimensions of the proposed bearings.

[0008] The aim of the present invention is to produce a damping bearing for a pivot of an axis of a watch mobile, in particular for the pivot of the balance staff, which is efficient and which has a low height, in particular for its use in a so-called extra-flat watch movement.

[0009] The present invention relates to a shock absorber for a pivot of an axis of a clockwork mobile according to claim 1.

[0010] The attached figures illustrate schematically and by way of example only one embodiment of a shock absorber according to the invention.

[0011] THE figures 1 et 2 illustrate an embodiment of the shock absorber according to the invention seen from above, respectively from below.

[0012] There figure 3 illustrates the shock absorber of the figures 1 et 2 seen in section.

[0013] The shock absorber 1 according to the invention comprises a flexible guide component 2 comprising a central rigid portion 20, an external rigid portion 21 and an elastic portion 22 connecting the central rigid portion 20 and the external rigid portion 21. Preferably and as illustrated in the figures, the flexible guide component 2 is in one piece.

[0014] The central rigid portion 20 has the shape of a setting in which a stone 3 and a counter-stone 4 are fixed, intended to ensure the pivoting of a pivot of an axis of a watch mobile (not illustrated). Traditionally, the stone 3 is pierced in its center to receive the pivot while the counter-stone 4 has a surface suitable for the pivoting of the pivot end. Preferably, there is a space between the stone 3 and the counter-stone 4 intended to receive the lubricant.

[0015] The outer rigid portion 21 is intended to be fixed or driven into or onto a fixed part (bridge or plate) of a watch movement. According to the illustrated embodiment, the outer rigid portion 21 has the shape of a ring and comprises on its outer periphery three driving zones 211 uniformly distributed over this periphery and serving for the actual driving of the flexible guide component 2, and of the shock absorber 1 in general, into or onto a fixed part of the watch movement.

[0016] Preferably, the elastic portion 22 connecting the central and external rigid portions 20 and 21 is formed of elastic arms 221, a first end of which is attached to the rigid central portion 20 while the other end is attached to the external rigid portion 21. In the illustrated embodiment, the elastic arms 221 are three in number, have essentially the same geometric and elastic characteristics and are uniformly distributed between the central and external rigid portions 20, 21.

[0017] The shock absorber 1 according to the invention further comprises a stop and centering member, hereinafter called the cover 5, integral (driven or fixed) with the flexible guide component 2. In the illustrated embodiment, the cover 5 comprises three driving zones 51 intended to allow the driving of the cover 5 inside the ring formed by the outer rigid portion 21 of the flexible guide component 2. Preferably, the cover 5 is driven into the outer rigid portion 21 so that the driving zones 51 of said cover 5 and the driving zones 211 allowing the driving of the outer rigid portion 21 into or onto a fixed part of the movement are not opposite each other but offset (see figure 2 ). This avoids the accumulation of tolerances for hunting.

[0018] The cover 5 comprises an opening 50 through which a pivot of an axis of a watch mobile can pass for its pivoting in the jewel 3 and the counter-jewel 4. This opening 50 serves as an axial and / or radial stop for the tigeron of the pivot of the watch mobile of which the shock absorber 1 is a bearing.

[0019] The cover 5 is also arranged to participate in the centering or radial positioning of the central rigid portion 20 in the event of an impact. To do this, the cover 5 comprises a first conical portion 52 intended to cooperate with a corresponding second inverted conical portion 201 of the central rigid portion 20 of the flexible guide component 2. Preferably, one or other of the conical portions 52 or 201 comprises a rounded or domed surface. In the illustrated embodiment, it is the inverted conical portion 201 of the central rigid portion 20 which is slightly rounded (see figure 3 ). This straight cone / rounded cone combination is more efficient than a combination of two straight cones and can also be simpler to produce depending on the processes and materials used for the central rigid portion 20 or the cover 5.

[0020] The cover 5 is arranged so that the elastic arms 221 are not in contact with said cover 5 when the latter is driven into the outer rigid portion 21 of the flexible guide component 2 (see figure 3 ). The elastic arms 221 are thus in a vacuum, free to deform axially and radially without contact with the cover 5. The cover 5 can take any shape appropriate to its functions and have the necessary cutouts or clearances depending on the clockwork mobile for which the shock absorber 1 is intended (the figures 1, 2 illustrate a cutout for the passage of the sting of an anchor in the case where the shock absorber 1 is used as a bearing for the axis of a balance cooperating with said anchor).

[0021] At rest, the position of the central rigid portion 20 and the stones 3 and counter-stone 4 is ensured by the elastic arms 221 as well as by the conical portions 52, 201 of the cover 5 and of the central rigid portion 20 in abutment with each other ( figure 3 ).

[0022] In the event of an impact on the clockwork mobile pivoted in the shock absorber 1, regardless of the direction of this impact, the jewels 3 and counter-jewels 4 are pushed by the pivot of said mobile and the central rigid portion 20 of the elastic guide component 2 moves radially and / or axially against the action of the elastic arms 221. The axial and / or radial displacement of the central rigid portion 20 is limited by the pivot pin coming into abutment in the opening 50 of the cover 5.

[0023] The rigid portion 20 and the stones 3 and counter-stones 4 return to their appropriate centered position under the combined action of the elastic arms 221 returning to their position and the conical portions 52, 201 of the cover 5 and the central rigid portion 20 sliding over each other.

[0024] Preferably, the cover 5 and the central rigid portion 20 and in particular their respective conical portion 52, 201 are arranged so that, in the rest position of the damper, the cover 5 driven into the flexible guide component 2 and the conical portions 52, 201 in contact, the elastic portion 22 and the elastic arms 221 are prestressed. This makes it possible to block or limit the vibration of the elastic arms 221 (resonance) due to the normal movement of the mobile pivoted in the damper 1. This prestressing also makes it possible to determine a threshold for triggering the damper: an impact below this threshold does not cause the displacement of the rigid central portion 20 of the flexible guide component 2 relative to the cover 5.

[0025] Preferably, the rigid central portion 20 of the flexible guide component 2 comprises at least one washing opening 202 allowing the shock absorber to be washed and in particular the cleaning of any lubricant between the stone 3 and the counter-stone 4.

[0026] Preferably, the outer rigid portion 21, the central rigid portion 20 and the elastic portion 22 are essentially in the same plane when the shock absorber is at rest. In addition, even more preferably, the cover 5 does not protrude, on either side, from the flexible guide component 2 (see figure 3). The thickness of the damper is then solely determined by the greatest thickness of the flexible guide component 2. This ensures a damper 1 of very low height, suitable for an extra-flat watch movement. Alternatively, the cover 5 could protrude from the flexible guide component 2 on the axis side (below), for example to stiffen the stop formed by the opening 50.

[0027] The above embodiment has been described as an example. Other variants are possible without departing from the scope of the invention.

[0028] The flexible guide component 2 described is a single-piece component. The advantage of a single-piece component is that it reduces the number of assembly operations. In addition, this component is well suited to single-piece manufacturing in several types of materials: Liga, steel, CuBe, etc. Alternatively, the flexible guide component could be composed of several parts attached to each other by any suitable means.

[0029] The elastic portion 22 connecting the rigid portions of the flexible guide component consists of three arms 221 in the illustrated embodiment. These arms could be at least 2 in number, and preferably an odd number, in particular 3 or 5. Preferably, these elastic arms are symmetrical to ensure the balance of the system.

[0030] The use of elastic arms also allows great flexibility in the dimensioning of the shock absorber: by varying certain parameters such as length and flexion, it is possible to define the preload or the trigger threshold (reaction to shock) of the shock absorber. It is also possible to dimension the shock absorber according to the mass of the pivoted mobile: a heavy mobile will need a less flexible elastic portion than a light mobile. A person skilled in the art is able to determine the ideal dimensions and characteristics of the elastic portion 22 of the flexible guide component according to the intended use of the shock absorber.

[0031] Alternatively, the elastic portion 22 could have any suitable shape (membrane, spring, etc.).

[0032] In the above embodiment, the damper comprises a traditional stone 3 and counter-stone 4. Alternatively, the stone and the counter-stone could be made in one piece to form a single-piece pivot bearing driven into the rigid central portion 20 of the flexible guide component. In another variant, the damper could not comprise an attached bearing as such, the rigid central portion 20 then comprising a blind hole serving as a pivot bearing for the pivot.

[0033] Generally speaking, a shock absorber intended for the pivoting of a pivot of an axis of a watch mobile according to the invention comprises: a flexible guide component comprising a central rigid portion in which at least one pivot bearing is formed or fixed on or in which a pivot of the axis of a watch mobile is pivoted, an external rigid portion intended to be driven or fixed in or on a fixed part of a watch movement and an elastic portion connecting the central rigid portion to the external rigid portion and arranged to allow radial and axial movement of the central rigid portion relative to the external rigid portion when it is deformed; a stop and centering member mounted integral with the external rigid portion of the flexible guide component and comprising an opening intended to receive the pivot of the axis of the watch mobile and to serve as a stop for it and a first conical portion arranged to cooperate with a corresponding second conical portion of the central rigid portion of the flexible guide component.

[0034] The shock absorber is arranged so that the first and second conical portions are in contact and ensure the adequate positioning of the rigid central portion when the shock absorber is at rest, so that the rigid central portion can move, against the action of the elastic portion, radially and / or axially relative to the stop and centering member during an impact transmitted by the pivot to the pivot bearing, this movement being limited by the pivot coming into abutment in the opening of the stop and centering member, and so that the elastic portion and the cooperation of the first and second conical portions ensure the adequate repositioning of the rigid central portion after the impact.

[0035] Preferably, the stop and centering member is arranged so that, when the shock absorber is at rest, the first and second conical portions are in contact in a position in which the elastic portion is under stress, this stress determining a trigger threshold for the shock absorber and preventing the shock absorber from being set into resonance by the normal movements of the clockwork mobile.

[0036] Alternatively, the resilient portion comprises at least two, preferably an odd number of resilient arms extending between the central rigid portion and the outer rigid portion of the flexible guide component.

[0037] Preferably, the flexible guide component came as a single piece or monobloc.

[0038] Preferably, the pivot bearing is formed of a stone and a counter stone both driven into the central rigid portion of the flexible guide component.

[0039] The present invention therefore provides a shock absorber or elastic bearing for supporting the pivot of the axis of a watch mobile which is very efficient since the combination of the elastic portion and the conical portions guarantees optimal recentering or repositioning after a shock regardless of the direction of the shock. The shock absorber according to the invention is particularly well suited to the pivoting of the balance staff in a watch movement. In addition, due to its construction, the shock absorber offers great flexibility of use and adapts to many mobiles. By choosing the appropriate properties of the elastic portion, this shock absorber can be used with light or heavy balances.The low number of components and the possibility of producing the flexible guide component in a single piece make the shock absorber according to the invention a very compact system, easy to assemble and also easy to manufacture because it is possible to use a wide variety of materials and manufacturing processes, in particular traditional and well-controlled processes and materials (turning, CuBe, steel, etc.). Finally, the thickness of the shock absorber according to the invention can be greatly reduced compared to the shock absorbers of the prior art, in particular those with double centering cones, without impairing its effectiveness in absorbing shocks. The shock absorber according to the invention is therefore entirely suitable for use in an extra-flat movement, in particular in an extra-flat escapement line.

Claims

1. Shock-absorber bearing-block(1) for a pivot of a axis of a timepiece mobile comprising: ∘ a flexible guide component (2) comprising a central rigid portion (20) in which at least one pivot bearing (3, 4) is formed or fixed, on or in which a pivot of the axis of a timepiece mobile is pivoted, an outer rigid portion (21) intended to be fixed or driven into or onto a fixed part of a timepiece movement comprising the mobile and an elastic portion (22) connecting the central rigid portion (20) to the outer rigid portion (21) and arranged to allow a radial and axial displacement of the central rigid portion (20) with respect to the outer rigid portion (21) when it is deformed; ∘ a stop and centring member (5) mounted in a fixed manner on the outer rigid portion (21) of the flexible guide component (2) and comprising an opening (50) intended to receive the pivot of the axis of the timepiece mobile and arranged to act as a stop for said pivot and a first portion (52); ∘ the central rigid portion (20) can move, against the action of the elastic portion (22), radially and / or axially with respect to the stop and centring member (5) during a shock transmitted by the pivot to the pivot bearing (3, 4), this displacement being limited by the pivot coming to a stop in the opening (50) of the stop and centring member (5); characterised in that the central rigid portion (20) of the flexible guide component (2) comprises a second conical portion (201) arranged to cooperate with the first portion (52), which is also conical, of the stop and centring member (5) so that when the shock-absorber bearing-block is inoperative, the first and second conical portions (52, 201) are in contact and ensure the correct positioning of the central rigid portion (20), the elastic portion (22) and the cooperation of the first and second conical portions (52, 201) ensuring the correct repositioning of the central rigid portion (20) after the shock; and in that the stop and centring member (5) does not protrude beyond the flexible guide component (2), the thickness of this component (2) determining the thickness of the shock-absorber bearing-block (1).

2. Shock-absorber bearing-block (1) as claimed in the preceding claim, characterised in that, when the shock-absorber bearing-block is inoperative, the central and outer rigid portions (20, 21) and the elastic portion (22) of the flexible guide component are essentially located in the same plane.

3. Shock-absorber bearing-block (1) as claimed in any one of the preceding claims, characterised in that the stop and centring member (5) is arranged so that, when the shock-absorber bearing-block (1) is inoperative, the first and second conical portions (52, 201) are in contact and the central rigid portion (20) in a position relative to the stop and centring member (5), in which the elastic portion (22) is under constraint, this constraint determining a triggering threshold for the shock-absorber bearing-block and preventing the flexible guide component (2) and its elastic portion (22) from being brought into resonance by reason of the normal movements of the timepiece mobile.

4. Shock-absorber bearing-block (1) as claimed in any one of the preceding claims, characterised in that the elastic portion (22) comprises at least two, preferably three or five or an odd number of elastic arms (221) extending between the central rigid portion (20) and the outer rigid portion (21) of the flexible guide component.

5. Shock-absorber bearing-block (1) as claimed in any one of the preceding claims, characterised in that the flexible guide component (2) is made from a single piece or is monobloc.

6. Shock-absorber bearing-block (1) as claimed in any one of the preceding claims, characterised in that the pivot bearing is formed of a jewel (3) and of a counter-jewel (4), both driven into the central rigid portion (20) of the flexible guide component (2).

7. Shock-absorber bearing-block (1) as claimed in any one of the preceding claims, characterised in that the outer rigid portion (21) of the flexible guide component (2) has at least two first driving-in zones (211) intended to be driven into or onto a fixed part of a timepiece movement; in that the stop and centring member (5) also comprises at least two second driving-in zones (51) ; and in that, when the stop and centring member (5) is mounted in a fixed manner on the flexible guide component (2), the first and second driving-in zones (211, 51) are not located facing each other but are offset.

8. Shock-absorber bearing-block (1) as claimed in any one of the preceding claims, characterised in that one of the first or second conical portions (52, 201) of the stop and centring member (5) or of the central rigid portion (20) of the flexible guide component (2) has a rounded or domed surface.

9. Timepiece comprising a shock-absorber bearing-block (1) as claimed in any one of the preceding claims.

Images