UNIT FOR ANCHOR STOPPING OF A CLOCK MECHANISM

Description

technical field

[0001] The present invention relates to an assembly for an anchor escapement, comprising an anchor, a plate, and a pin integral with the plate, intended to cooperate with each other and with an escape wheel in a service configuration, while providing protection against overturning. The anchor is without a tang and comprises, on the one hand, an entry pallet and an exit pallet, intended to cooperate alternately with the escape wheel, and, on the other hand, a fork intended to cooperate with the pin and the plate and comprising first and second horns defining a fork entry. The plate is at least partially situated at the same level as the pin, along the direction of the plate's thickness. The plate has a generally cylindrical anti-overturning wall in which a notch is formed in a region adjacent to the pin. The anchor,the platform and the peg being shaped and dimensioned in such a way that, in the service configuration, the anti-tipping wall is capable of defining a stop for the first and second horns. State of the art

[0002] An escapement comprising an assembly meeting the above characteristics was already disclosed in prior art, a long time ago.

[0003] Indeed, patent CH44855 dating from 1909 describes such an escapement, of reduced thickness compared to conventional escapements thanks to the absence of a dart on the fork, the dart being typically arranged at a different level than the fork horns in conventional escapements.

[0004] Patent DE867671 describes another example of an escapement in which the anchor has a special structure designed to simplify its manufacture by eliminating the need for an integral tang, while still offering a level of security equivalent to that of a conventional tanged anchor. To this end, the patent specifies that the anchor includes a fork ending in a point designed to engage with the periphery of a small plate, thus acting as a conventional tang.

[0005] Despite the advantages put forward in these documents, the corresponding escapements have not become established on the market and traditional Swiss lever escapements, including a dart, are by far the most widespread, and have been for several decades.

[0006] The Applicant has conducted extensive studies on escapement geometries and has been able to highlight a drawback of the escapement mentioned above. Indeed, the escapement as described in the previously cited Swiss patent presents a risk of malfunction in the event of a rebat, since the horn against which the balance wheel pivot abuts in this situation is liable to penetrate the notch in the balance wheel when the balance wheel changes direction. This poses a risk of the escapement stopping abruptly, and consequently of the corresponding watch movement, and could even lead to damage to the pallet fork. Disclosure of the invention

[0007] A main objective of the present invention is to provide an assembly enabling the realization of an escapement with safe operation and reduced size compared to conventional escapements.

[0008] To this end, the present invention relates more particularly to an assembly of the type indicated above, characterized by the fact that the anchor, the plate and the peg are further shaped and dimensioned in such a way that, in the service configuration, each of the horns is capable of penetrating inside the notch exclusively when the peg is at least partially located in the entrance of the fork.

[0009] Thanks to these features, the only configuration of the assembly according to the invention in which a horn can enter the notch of the plate during operation is the one in which this horn must precisely enter the notch to allow the normal pivoting of the fork on either side of the dead center. This results in a reduced-thickness escapement with completely secure operation.

[0010] Preferably, each of the fork's tines has an inner wall delimiting the fork's entrance and an outer wall shaped and dimensioned in such a way that, in a rebat situation, the distance between the point of contact of the peg on the outer wall of the tine concerned and the end of the outer wall closest to the inner wall is greater than the distance between the peg and that of the junctions between the anti-reversal wall and the notch that is closest to the tine concerned.

[0011] Thanks to these specific geometric characteristics, each horn has a shape and dimension such that it cannot enter the notch of the plate in a rebat situation but can only enter it when the peg is at least partially located in the fork.

[0012] According to a preferred embodiment, the anchor having a rod connecting the entry and exit pallets to the fork and capable of pivoting between two extreme positions, in the service configuration, by defining a maximum angle of deflection of the anchor, it can advantageously be provided that the external wall of each of the horns has, from its end closest to the internal wall, a first portion defining a safety surface and having a mean angle, with reference to the rod such that the safety surface is substantially tangent to the anti-rollover wall when it is located opposite the latter, then a second portion having an angle of the order of 0 to 60° with reference to the rod, preferably less than 45°, for example 30°, and extending at least to the point of contact of the pin on the external wall in the re-rolling situation.

[0013] In a particular embodiment variant, it can be provided that the peg is made integral with the plate by means of a support made in one piece with the plate.

[0014] As an additional or alternative option, it is possible to have the ankle supported directly by the pendulum.

[0015] In general, the present invention also relates to an escapement comprising an assembly meeting the characteristics stated above associated with an escape wheel.

[0016] According to a preferred embodiment, it can be provided that this escapement is intended to be arranged, in the service configuration, in such a way that the distance between the axes of rotation of the anchor and the plate is at least equal to twice the distance between the axes of rotation of the anchor and the escape wheel.

[0017] Preferably, the escapement is intended to be arranged, in the service configuration, in such a way that the axes of rotation of the escape wheel, anchor and plate are coplanar.

[0018] The present invention also relates to a watch movement comprising an escapement meeting the above characteristics, and possibly including limiting pins arranged on either side of the anchor to define its maximum travel, as well as a timepiece equipped with such a watch movement. Brief description of the drawings

[0019] Other features and advantages of the present invention will become more apparent upon reading the detailed description of a preferred embodiment that follows, made with reference to the accompanying drawings given by way of non-limiting example and in which: THE Figures 1a and 1brepresent the same simplified top view of a watch movement assortment, respectively, of the conventional Swiss lever type and according to a preferred embodiment of the present invention; figures 2a and 2b represent a simplified side view of a portion of the respective assortments of Figures 1a and 1b ; THE figures 3a to 3n represent the same simplified top view of a portion of the assortment according to the preferred embodiment of the present invention as illustrated in the figure 1b , in different successive configurations; the figures 4a, 4b and 4c represent the same simplified top view of part of a watch movement assortment in a rebating situation, respectively according to a first prior art construction, according to a second prior art construction and according to the preferred embodiment of the invention as illustrated in the figure 1b , and the figure 5represents a schematic top view of a plurality of anchors according to different respective embodiments of the present invention. Method(s) of embodiment of the invention

[0020] THE figures 1a, 1b And 2a, 2b These illustrations represent simplified views, firstly from above and, secondly, partial and side views, of a watch movement assembly, respectively, of the conventional Swiss lever type and according to a preferred embodiment of the present invention. A comparative examination of these different views highlights the structural characteristics that differentiate the component assembly according to the present invention from a component assembly according to the most widespread prior art on the market.

[0021] As is well known, the Swiss lever escapement 100 illustrated on the figures 1a And 2aIt comprises an escape wheel 102 integral with an escape pinion 104 and arranged to cooperate with the inlet pallets 106 and outlet pallets 108 of an anchor 110, intended to pivot on its axis 112. A rod 114 connects the pallets 106 and 108 to a fork whose inlet is delimited by two horns 116. The fork is surmounted by a dart 118 intended to provide protection against tipping. Inlet limiting pins 120 and outlet limiting pins 122 are typically provided to limit the amplitude of rotation of the anchor 110. The anchor is intended to cooperate with a double plate, notably to transmit some of the energy received from the escape wheel to the balance wheel (not visible) to maintain its oscillations.The double plate includes, for this purpose, a small plate 124 whose cylindrical periphery defines an anti-overturning wall by its cooperation with the dart 118, this wall being provided with a notch 126 intended to allow the rotation of the anchor 110 on either side of the dead point, while providing sufficient space to define a passage for the dart 118. The small plate 124 is generally integral with a large plate 128 by means of a barrel 130, the large plate 128 carrying a pin 132 intended to cooperate with the fork of the anchor 110 in order, on the one hand, to trigger a rotation of the anchor 110 at each alternation by exerting an adequate force on a first horn 116 and, on the other hand, to receive an impulse from the other of the horns 116 before exiting the fork.

[0022] The illustration of the figure 2a more specifically allows us to highlight the thickness of the whole that has just been described.

[0023] An escapement 1 according to a preferred embodiment of the invention is illustrated in the figures 1b And 2b By way of non-limiting example, it appears that this escapement comprises an escape wheel 2 integral with an escape pinion 4 and arranged to cooperate with the inlet pallets 6 and outlet pallets 8 of an anchor 10, intended to be pivoted on its axis 12. A rod 14 connects the pallets 6, 8 to a fork whose inlet is delimited by two horns 16, 18. As will be seen later, the horns 16, 18, in addition to their conventional function, are intended here to provide protection against overturning. Inlet limiting pins 20 and outlet limiting pins 22 are typically provided to limit the amplitude of rotation of the anchor 10.

[0024] The anchor 10 is designed to cooperate with a reduced-thickness plate 24, in reference to the conventional double plate. The plate 24 has a cylindrical periphery defining an anti-rollover wall through its interaction with the lugs 16 and 18. This wall is provided with a notch 26 intended to allow the anchor 10 to rotate on either side of the dead center, while providing sufficient space to define a passage for the lugs 16 and 18. The plate 24 has a small radial protrusion 28 defining a support for a pin 32 intended to cooperate with the fork of the anchor 10, as will become clearer from the explanations that follow, in relation to the description of the figures 3a to 3n .

[0025] Thus, the fact that anchor 10 is without a stinger allows for a reduction in its thickness, as well as that of the platform, as can be seen from a comparative examination of the figures 2a and 2b .

[0026] However, it should also be noted that the horns 16 and 18 replace the dart in its anti-overturning function and are wider than the typical width of the dart. Therefore, the notch 26 in the plate 24 must be enlarged in reference to conventional escapements, and the plate 24 itself must also be enlarged accordingly. These modifications necessitate lengthening the anchor rod 14 if the escape wheel 2 remains unchanged in reference to a conventional Swiss lever escapement, as is particularly evident from a comparative examination of the Figures 1a and 1b , in such a way that the fork can make a greater movement without changing the angle of travel of the anchor 10.

[0027] The operation of the escapement 1 according to this preferred embodiment of the invention will now be described in relation to the figures 3a to 3nwhich illustrate successive configurations of this escapement in operation, in the same simplified top view on which the escape wheel 2 is no longer shown.

[0028] There figure 3a This represents the entire escapement assembly when the balance wheel (not visible) is in the additional downward angle phase, with the anchor 10 and escape wheel at rest. In this configuration, the anchor 10's rod 14 rests against the exit limiting pin 22, and the anchor 10's exit pallet 8 rests against a tooth of the escape wheel 2.

[0029] It can already be noted at this stage that if the corresponding watch movement were to suffer a shock, in this configuration, such that the escape wheel would release the anchor 10, the latter could not pivot insofar as the horn 16 is arranged immediately near the wall of the plate 24, the latter thus fulfilling the role of an anti-overturning wall.

[0030] There figure 3b represents a configuration in which the peg 32 of the plate 24 is about to enter the fork while it is still located opposite the horn 18. In this configuration, the horn 16 is partially located opposite the notch 26 of the plate 24 but it still remains close to the anti-overturning wall and therefore maintains the safety against the overturning of the anchor 10.

[0031] THE figures 3c And 3drepresent the release phase during which the pin 32 comes into contact with the horn 16 and acts upon it to rotate the anchor 10, which then leaves its stop position. At the same time, the anchor 10 begins to receive an impulse from the escape wheel 2, in a conventional manner.

[0032] The impulse phase continues until the configuration of the figure 3g , passing through neutral, illustrated on the figure 3e , the anchor 10 transmitting to the balance wheel a fraction of the energy received from the escape wheel 2, via the pin 32 of the plate 24 between the dead center and the end of the impulse phase shown on the figure 3g . At this stage, the anchor 10 is blocked against the entry limiting pin 20 by the pull exerted by the escape wheel 2 on the entry pallet 6.

[0033] The pin 32 then comes out of the fork, as shown on the figure 3hand the balance wheel begins an additional upward angle phase. This figure shows that the exit of the pin 32 from the fork coincides with the moment when the horn 18 reaches the immediate vicinity of the anti-overturning wall of the plate 24, thus ensuring the locking of the anchor 10 in the position shown, as is also apparent from the view of the figure 3i .

[0034] There figure 3j represents the configuration corresponding to the end of the next additional downward angle phase, once the pin 32 has already entered the fork opening and when it comes into contact with the horn 18 to begin the next release phase, in the opposite direction. With the pin 32 located in the fork opening, the notch 26 of the plate is positioned opposite the horn 18 to allow the anchor 10 to pivot counterclockwise in the view of the figure 3j .

[0035] THE figures 3k, 3l and 3m represent respectively the continuation of the release phase, the passage through the dead spot, then the next impulse phase.

[0036] There figure 3n illustrates the beginning of the next ascending supplementary angle phase, the following descending supplementary angle phase of which again corresponds to the illustration of the figure 3a The configuration illustrated on the figure 3n corresponds to the moment when the peg 32 has just left the fork and we observe that the horn 16 is then again located in the immediate vicinity of the anti-reversal wall of the plate 24.

[0037] THE figures 4a, 4b and 4c present three different types of escapements in a rebat situation and their comparative examination makes it possible to highlight certain particularities of the present invention.

[0038] There figure 4aThis illustrates the rebat situation for the previous escapement as described in patent CH44855 cited above, and demonstrates the limitations of this escapement in terms of operational safety. As mentioned previously, the Applicant observed that this escapement presented a high risk of jamming in the event of rebat, since the horn 216 of the fork, against which the pin 232 abuts in a rebat situation, is liable to penetrate the notch 226 of the plate 224 and block the rotation of the plate 224 and thus the operation of the corresponding watch movement.

[0039] There figure 4bpresents the rebat situation in the case of the conventional Swiss lever escapement, in which the horns 116 and the dart 118 are shaped, with respect to the plate 124 and its notch 126, in such a way that the horns 116 cannot penetrate the notch 126 in a rebat situation, due to the positioning of the dart 118 against the anti-reversal wall of the plate 124.

[0040] It emerges from the figure 4c that the fork of the anchor 10 has a shape that is substantially different from the typical shape of a conventional anchor fork, in order to optimize the nature of its interaction with the peripheral wall of the plate 24.

[0041] Indeed, each of the frog's lugs 16, 18 has an internal wall 36 delimiting the frog's entrance and an external wall 38 shaped and dimensioned in such a way that, in a rebat situation, the distance between the point of contact of the peg 32 on the external wall 38 of the relevant lug (lug 16 in the configuration illustrated on the figure 4c ) and the end 40 of the outer wall 38 closest to the inner wall 36 is greater than the distance between the peg 32 and that of the junctions 42 between the anti-roll wall and the notch 26 which is closest to the horn in question. Thanks to such a geometric arrangement, the horns 16, 18 cannot penetrate the notch 26 in a rebat situation, as was the case with the prior art mentioned above, which is clearly evident from a comparative examination of the illustrations of figures 4a and 4c .

[0042] In addition, the outer wall 38 of each of the horns 16, 18 has, from its end 40 closest to the inner wall 36, a first portion 38a defining a safety surface and having a mean angle, with reference to the rod 14 of the anchor 10, such that the safety surface is substantially tangent to the anti-rolling wall when it is located opposite the latter (i.e. essentially when the anchor 10 is in the rest phase), then a second portion 38b having an angle of the order of 0 to 60° with reference to the rod 14, preferably less than 45°, for example 30°, and extending at least to the point of contact of the pin 32 on the outer wall 38 in the re-rolling situation. Thus, the first portion 38a likely to come into contact with the anti-tipping wall of the platform 24 offers a contact surface with the latter inducing limited friction.Furthermore, this geometry defines horns that are wider than those of the prior art, and therefore less fragile and less susceptible to damage in the event of an impact. The orientation of the second portion 38b further increases the width of the horns 16, 18, not only to make them stronger but also to ensure that the geometric condition stated above, in relation to the rebat situation, is met; that is, that the distance between the point of contact of the peg 32 on a horn in a rebat situation and the end 40 of the outer wall 38 of that horn is much greater than the distance between the peg 32 and the nearest junction 42 of the horn in question.

[0043] It thus appears from the figure 4cthat the assembly according to the present invention offers a level of security equivalent to that of the assembly for a Swiss lever escapement, while having a reduced thickness compared to the latter. Indeed, the release and impulse functions performed by the inner wall 36 of the fork are at the same level as the anti-overturning function performed by the outer wall 38 of the fork, whereas these functions are performed at different levels in a traditional lever escapement with a dart.

[0044] A comparative examination of figures 4b and 4c Furthermore, it allows us to observe an additional advantage of the present invention with reference to a conventional Swiss lever escapement. It appears on the figure 4b that the elongation of the balance wheel at the moment of the rebat is on the order of 330 to 340 degrees (360°-α on the figure 4b ) whereas it can be greater than 360 degrees in the case of the invention, as illustrated in the figure 4c , from which it appears that the elongation here is 360°+β (β typically having a value on the order of a few degrees), which is more favorable from the point of view of the isochronism of the corresponding oscillator.

[0045] Thanks to the characteristics just presented, it is possible to produce an escapement conforming to the characteristics of the invention with reduced thickness in reference to a conventional Swiss lever escapement but presenting a level of security at least equivalent to that of the latter.

[0046] The preceding description focuses on describing a particular embodiment by way of non-limiting illustration, and the invention is not limited to the implementation of certain specific features just described, such as, for example, the geometry of the anchor 10 or the exact shape of its fork, or even the shape of the balance wheel pin or its support for securing it to the balance wheel. Indeed, the pin can be secured to the balance wheel by any suitable means. EP 2924517, in particular, describes such a configuration. It is also possible for the pin to be carried directly by the balance wheel, for example, without departing from the scope of the invention. Similarly, the axes of rotation of the escape wheel, the anchor, and the balance wheel can be coplanar or not without impacting the implementation of the invention.

[0047] With regard more specifically to the geometry of anchor 10, the figure 5represents a schematic top view of a plurality of anchors according to different respective embodiments of the present invention, and allows an overview of the flexibility available to a person skilled in the art in designing an anchor that meets the characteristics of the invention.

[0048] The person skilled in the art will encounter no particular difficulty in adapting this teaching to the implementation of an assembly enabling the realization of an escapement in which the anchor is without a tang but its fork is arranged in such a way that its horns can only enter the notch of the plate when the pin of the latter is located at least partially inside the fork.

Claims

1. Assembly for a lever type escapement (1), including pallets (10), a roller (24) and a pin (32) fastened to said roller (24), intended, in a service configuration, to cooperate with one another and with an escape wheel (2) whilst being safe against knocking, the pallets (10) having no guard pin and including, on the one hand, an entry pallet (6) and an exit pallet (8), intended to cooperate alternately with the escape wheel (2) and, on the other hand, a pallet fork intended to cooperate with said pin (32) and said roller (24) and including first and second horns (16, 18) delimiting a pallet fork entry, said roller (24) being at least partly situated at the same level as said pin (32), in the direction of the thickness of the roller (24), said roller (24) having an anti-overbanking wall of cylindrical general shape in which a notch (26) is formed, in a region adjacent to said pin (32), said pallets (10), said roller (24) and said pin (32) being conformed and dimensioned in such a manner that, in the service configuration, said anti-overbanking wall is able to define an abutment for said first and second horns (16, 18), characterized in that said pallets (10), said roller (24) and said pin (32) are moreover conformed and dimensioned in such a manner that, in the service configuration, each of said horns (16, 18) is able to penetrate to the interior of said notch (26) exclusively when said pin (32) is at least partly situated in the entry of said pallet fork.

2. Assembly according to Claim 1, characterized in that each of said horns (16, 18) of said pallet fork has an internal wall (36) delimiting the entry of said pallet fork and an external wall (38) conformed and dimensioned in such a manner that, in a knocking situation, the distance between the point of contact of said pin (32) on the external wall (38) of the horn (16, 18) concerned and the end (40) of said external wall (38) nearest the internal wall (36) is greater than the distance between the pin (32) and that of the junctions (42) between the anti-overbanking wall and the notch (26) nearest the horn (16, 18) concerned.

3. Assembly according to Claim 2, the pallets (10) including a lever (14) connecting said entry and exit pallets (6, 8) to said pallet fork and able to pivot between two extreme positions, in the service configuration, defining a maximum angle of travel of the pallets (10), characterized in that said external wall (38) of each of said horns (16, 18) has, from its end (40) nearest said internal wall (36), a first portion (38a) defining a safety surface and having a mean angle relative to said lever (14) such that said safety surface is substantially tangential to said anti-overbanking wall when it is situated facing the latter, then a second portion (38b) at an angle of the order of 0 to 45° relative to said lever (14) and extending at least to the point of contact of said pin (32) on said external wall (38) in the knocking situation.

4. Assembly according to any one of the preceding claims, said pin (32) being fastened to said roller (24) by means of a support (28), characterized in that said support (28) is made as one with said roller (24).

5. Assembly according to any one of Claims 1 to 3, said pin (32) being fastened to said roller (24) by means of a support, characterized in that said support is a balance wheel.

6. Lever type escapement (1) including an assembly according to any one of the preceding claims associated with an escape wheel (2).

7. Escapement (1) according to Claim 6, characterized in that it is intended to be arranged, in the service configuration, in such a manner that the distance between the rotation axes of the pallets (10) and of the roller (24) is at least equal to twice the distance between the rotation axes of the pallets (10) and of the escape wheel (2).

8. Escapement (1) according to Claim 6 or 7, characterized in that it is intended to be arranged, in the service configuration, in such a manner that the rotation axes of the escape wheel (2), of the pallets (10) and of the roller (24) are coplanar.

9. Timepiece movement including a lever type escapement (1) according to any one of Claims 6 to 8.

10. Timepiece movement according to Claim 9, including banking pins (20, 22) arranged on respective opposite sides of the pallets (10) to define its maximum angle of travel.

11. Timepiece including a timepiece movement according to Claim 9 or 10.