Escapement mechanism for timepiece

Abstract

The present invention relates to a direct escapement mechanism (1) having an escape wheel (2) provided with a series of peripheral teeth (3), and an anchor (4), having an entry-pallet (10) and an exit-pallet (11) each having a locking plane (10p, 11p) and also having a fork (43). It also comprises a pin (6) which can be rigidly connected to a regulating organ (5) to cooperate at each alternation of said regulating organ (5) with the fork (43) of the anchor in order to unlock at least partially said anchor from the escape wheel (2) as well as at least one impulse pallet (9) which can be rigidly connected to said regulating organ (5) to cooperate with a tooth (3) of the escape wheel to transmit a direct impulse to said regulating organ (5). Typically, at least the teeth (3) of the escape wheel or one of the entry-pallets or exit-pallets (11) comprises in the extension of said locking plane (10p, 11p) a inclined plane (3i, 10i, 11i) arranged to provide an indirect impulse to said regulating organ (5) during a movement of said pallet in the path C of the escape wheel (2) by rotating the anchor (4) on its axis (X3). The invention also relates to a timepiece incorporating such an escapement mechanism.

Claims

1. A direct escapement mechanism (1) for a timepiece, comprising: an escape wheel (2), rotatable about a first axis of rotation (X1) and provided with a series of peripheral teeth (3), each having a locking plane (3p), said teeth (3) defining by their ends during rotation of the escape wheel a circular trajectory C, and an anchor (4), rotatable around a second axis of rotation (X3) between two end locking positions delimited by pins (7, 8), said anchor having an entry-pallet (10) and an exit-pallet (11), each having a locking plane (10p, 11p) and arranged on the anchor in such a way that each pallet cooperates into abutment on its locking plane (10p, 11p) with the locking plane (3p) of a tooth (3) of the escape wheel in each of said locking positions, said anchor (4) further having a fork (43), and at least a further pin (6) which can be rigidly connected to a regulating organ (5) pivoting around a third axis of rotation (X2) to cooperate at each alternation of said regulating organ (5) with the fork (43) of the anchor in order to unlock at least partially said anchor from the escape wheel (2), at least one impulse pallet (9) capable of being rigidly connected to said regulating organ (5) to cooperate with a tooth (3) of the escape wheel to transmit a direct impulse to said regulating organ (5); wherein at least each tooth (3) of the escape wheel or at least one of the entry-pallets or exit-pallets (11) comprises in the extension of said locking plane (3p, 10p, 11p) an inclined plane (3i, 10i, 11i) having ends which delimit a micro-impulse angle comprised between 0.5 and 5, said angle being considered in relation to said axis of rotation (X3) of the anchor (4), said inclined plane (3p, 10i, 11i) being arranged to provide an indirect impulse to said regulating organ (5) during a movement of said pallet in the path C of the escape wheel (2) by rotating the anchor (4) on its axis (X3).

2. The direct escapement mechanism according to claim 1, wherein said angle delimited by the ends of said inclined plane (3i, 10i, 11i) is comprised between 0.5 and 2.

3. The direct escapement mechanism according to claim 1, wherein said inclined plane (3i, 10i, 11i) extends in a secant direction forming an acute angle i comprised between 30 and 70 with said locking plane (3p, 10p, 11p).

4. The direct escapement mechanism according to claim 1, wherein the fork (43) comprises two horns (44, 45) separated by a notch (46) and devoid of a guard pin or the like.

5. The direct escapement mechanism according to claim 4, wherein said horns (44, 45) of the fork (43) are symmetrical in relation to a straight line passing by the axis of rotation (X3) of the anchor and the centre of the notch (46) and extending from said notch (46) following an arc of a circle with a radius of curvature R1 and having at their free end a stud or finger (44e, 45e) protruding perpendicularly to the median plane of the anchor in which the horns extend.

6. The direct escapement mechanism according to claim 4, further comprising a circular flange (12) attachable to said regulating organ, said flange being centered on the axis of rotation of said regulating organ (5), the further pin (6) being embedded in said flange and movable without contact along an internal face of said horns during the locking phases of the escape wheel.

7. The direct escapement mechanism according to claim 5, wherein the radius of curvature R1 is comprised between 0.5 and 1.5 cm.

8. The direct escapement mechanism according to claim 6, wherein said flange has bevelled free ends in a vertical plane.

9. A timepiece having the direct escapement mechanism (1) according to claim 1, arranged to cooperate with the regulating organ (5) to which said further pin (6) and said impulse pallet (9) are rigidly connected.

10. The timepiece according to claim 9, wherein the regulating organ (5) is a sprung balance or a resonator mounted to move rotatably on a virtual pivot with knives.

11. The direct escapement mechanism according to claim 1, wherein said inclined plane (3i, 10i, 11i) extends in a secant direction forming an acute angle i comprised between 40 and 60 with said locking plane (3p, 10p, 11p).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other details of the invention will become clearer on reading the following description, with reference to the attached drawings in which:

(2) FIG. 1 shows an escapement mechanism according to the invention and an associated regulating organ such as a balance represented schematically, in a position called dead centre, without impulse or locking;

(3) FIG. 2 represents an enlargement of the end of a locking pallet of the escapement mechanism anchor of FIG. 1;

(4) FIG. 3 shows an enlargement of the escapement mechanism of FIG. 1, the various angles determining the self-start condition of the escapement according to the construction of the mechanism of the invention;

(5) FIGS. 4 to 9 show the various operational phases of the escapement mechanism according to the invention on a first alternation;

(6) FIGS. 10 to 16 show the various operational phases of the escapement mechanism according to the invention on a second alternation, corresponding to a coup perdu (vibration with no impulse);

(7) FIGS. 17 to 21 show different attachment positions of the anti-overbanking device of the escapement mechanism of the invention during two successive alternations.

(8) FIG. 22 shows an enlargement of the end of a tooth of the escape wheel in another embodiment of the escapement mechanism of FIGS. 1 to 21.

MODES OF CARRYING OUT THE INVENTION

(9) The present invention offers an detached escapement mechanism 1 of a new type, designed and arranged pour utilize and combine, in a detached escapement with direct impulses, the advantages associated to reliability, simplicity of adjustment and self-start of a Swiss anchor escapement well known by matchmakers for several decades.

(10) A particular embodiment of such an escapement mechanism 1 is represented on FIG. 1, corresponding to the dead centre of the escapement 1. Generally speaking, the escapement mechanism 1 is structurally similar to a Robin type escapement but several aspects are modified, as it is described below. The escapement mechanism comprises a escape wheel 2 provided with pointed teeth 3 and mounted to be rotatable around a first axis of rotation X1. Conventionally, this escape wheel 2 is associated to a escape-pinion (not shown) through which the escape wheel 2 is coupled to the finishing gear train and the drive source of a watch movement, for example a barrel spring, which transmits a driving torque to the escape wheel 2, which the latter distributes sequentially to a regulating organ 5 mounted to be rotatable around a second axis of rotation X2, in cooperation with an anchor 4, itself rotatable around a third axis of rotation X3, the axes of rotation X1, X2, X3 being parallel between each other. The regulating organ 5 can be made of a sprung balance well known by watchmakers or any other oscillating regulating organ, as for example a resonator with knives such as the one proposed by the applicant in patent application WO 2016/012281.

(11) The anchor 4 acts as a lever and comprises a plate 41 on which an entry-pallet 10 and an exit-pallet 11 are arranged, each presenting a locking plane 10p, 11p designed to form alternatively a locking surface in abutment for the teeth 3 of the escape wheel 2 in two end positions in rotation of the anchor 4 around its axis X3, called locking positions. In order to enable the pivoting of the anchor 4 from a locking position to the following one, said anchor comprises a fork 43 arranged at the end of an arm 42 extending from the plate 41 following a straight line linking the axis of rotation X3 of the anchor 4 with the axis of rotation X2 of the regulating organ 5. The fork 43 comprises two horns 44, 45 separated by a notch 46 and devoid of guard pin, finger, or analogous anti-overbanking safety element. These horns 44, 45 are symmetrical in relation to the straight line linking at the dead centre, the axis of rotation X3 and the axis X2 of the regulator, which passes also by the centre of the notch 46. Thanks to this fork 43, the anchor 4 cooperates, more particularly at the level of its notch 46, with a pin 6 mounted together with the regulating organ 5, for example with a coaxial plate of said regulating organ 5 and with which a direct impulse pallet 9 is further joined, which is propelled, at each alternation of the regulator 5, by a tooth 3 of the escape wheel 2. The travel of the anchor is limited by two pins 7, 8 which limit the angle A of the anchor 4 travel between 5 and 6 in relation to the axis X3 of the anchor 4.

(12) According to the invention, and as shown in detail on FIGS. 2 and 3, the entry-pallet 10 and the exit-pallet 11, in any case at least the exit-pallet 11, comprise, in the extension of their respective locking plane 10p, 11p, a inclined plane of indirect impulse 10i, 11i arranged to transmit an indirect micro-impulse to the regulating organ 5 when said pallets 10, 11 cross the path C defined by the end of the teeth 3 of the rotating escape wheel 2, during the rotation of the anchor 4 on its axis X3 between the two locking positions. These inclined planes 10i, 11i are advantageously formed on the locking pallets 10, 11 so that an angle , so-called micro-impulse, of a value comprised between 0.5 and 5, more particularly in the example represented between 1 and 2, preferably around 1.5 is formed between its ends and the axis of rotation X3 of the anchor 4. In addition, the indirect impulse planes 10i, 11i are arranged in the continuity of the locking plane 10p, 11p with an inclination according to an acute angle i; in practice in the range of 30 at 70, preferably between 40 and 60, preferably in the range of 50, in relation to said locking plane 10p, 11p. Thus, the indirect micro-impulse planes 10i, 11i provide a local break or recess d, in the extension and at the end of the locking planes 10p, 11p, whose length is determined according to the micro-impulse angle , calculated and adapted to ensure the automatic start of a regulating organ associated to the escapement 1 under the driving force of the gear after the stoppage of said regulating organ. Advantageously, the locking planes 10p, 11p of the pallets 10, 11 and of the teeth 3 are such that they rest plane on plane in a locking position of the escapement. In addition, the centre distance between the pivot of anchor X3 and the pivot X1 of the escape wheel 2 is adjusted so that at the dead centre of the escapement, the free end of the teeth 3 of the escape wheel bears by its locking plane substantially on the recess point d, in order to guarantee that the mere driving torque induces a sufficient draw to tip said end of the tooth 3 on the micro-impulse plane 10i, 11i after the stoppage of the regulating organ 5.

(13) In addition, the entry and exit pallets 10, 11 of anchor 4 are advantageously adjusted on the plate 41 in such a way that the locking and unlocking functions of the anchor in relation to the escape wheel 2, as well as the travel security of the latter in relation to said pallets are optimised. With reference to FIG. 2, pallets 10, 11 are therefore arranged so that in the locking positions a first pallet is in contact with a tooth 3 of the escape wheel on its locking plane on a distance defining a locking angle in the range of 2 at the axis of rotation X3 of the anchor while the other pallet is moved away from circle C of the escape wheel by a distance forming a security angle at the passage of the teeth 3 in the range of 1.5 at the axis of rotation X3.

(14) In addition, pallets 10, 11 ensure by their configuration and arrangement a slight draw, their inclined planes 10i, 11i offering a self-starting capability to the mechanism of the invention and the micro-impulse at each alternation, distinctive feature of a Swiss anchor escapement.

(15) In concrete terms, it is required for the mechanism 1 to start by itself under the torque of the escape wheel 2 that, from the locking position, the travel up to the dead centre (thus the half-angle of the anchor total movement) positions a inclined plane in the path C and not on a locking area. In addition, the passage from a pallet to another also requires that the pallet-escapement security be smaller than the half-angle of the travel of the anchor 4. Thus, an essential condition of the mechanism of the invention is defined in the following manner:

(16) $\frac{}{2}-$

(17) Thus, a combined or united track escapement between a Swiss anchor escapement and a Robin type direct escapement is actually obtained.

(18) In another embodiment of the invention represented in FIG. 22, the indirect impulse inclined plane can be provided not on the one of the entry-pallets 10 or exit-pallets 11 of the anchor 4 of the escapement mechanism 1, of the Swiss anchor escapement type, but directly at the free radial end of the teeth 3, in the form of a inclined plane 3i similar to the inclined plane 10i, 11i of the pallets 10, 11 on FIGS. 2 and 3 of the pin escapement type and forming therefore a micro-impulse angle , of a value comprised between 0.5 and 5, more particularly in the example represented between 1 and 2, in relation to the axis X3 of the anchor. The micro-impulse inclined plane 3i is provided at the free end of the tooth 3, in the continuity of its locking plane 3p but it is inclined according to an acute angle i, in practice in the range of 30 at 70 in relation to said locking plane 3p, preferably between 40 and 60, more preferably in the range of 50. Thus, the indirect micro-impulse planes 3i provide a local break or recess d, in the extension and at the end of the locking plane 3p, whose length is determined according to the micro-impulse angle , calculated and adapted to ensure the automatic start of a regulating organ associated to the escapement 1 under the driving force of the gear train after the stoppage of said regulating organ. Advantageously, the locking planes 10p, 11p of the pallets 10, 11 and of the teeth 3p are such that they rest plane on plane in a locking position of the escapement. In addition, the centre distance between the pivot of anchor X3 and the pivot X1 of the escape wheel 2 is adjusted so that at the dead centre of the escapement, the free end of the teeth 3 of the escape wheel rests by its locking plane substantially on the recess point d, in order to guarantee that the mere driving torque induces a sufficient draw of pallets 10, 11 to tip said end of the tooth 3 on the micro-impulse plane 3i after the stoppage of the regulating organ 5.

(19) The pallet 9 may also have an end shape adapted to receive and cooperate with the inclined plane 3i of the tooth 3 during the direct impulse in order to transmit a substantially constant torque.

(20) To avoid the overbanking or butting risks observed with the securities of the guard pin type like in the Robin escapement, the escapement mechanism 1 of the invention offers an anti-overbanking security device formed in a united way on the fork 43 of the anchor 4 and on the regulating organ 2, more particularly a flange made integral with the regulating organ 5. As previously indicated, the fork 43 of the anchor 4 is devoid of guard pin between its horns 44, 45. Indeed, the little angular path travelled by the anchor 4 does not allow to consider as it is initially planned in the Robin escapement, the implementation of such a guard pin cooperating with a safety-roller according to the usual shape of a Swiss anchor escapement for example, the adjustment difficulty of the escapement to avoid risks of butting being too significant to make the escapement viable at an industrial level. As a replacement, the fork 43 of the anchor 4 of the mechanism 1 according to the invention comprises two horns 44, 45 symmetrical in relation to a straight line passing by the axis of rotation X3 of the anchor and the centre of the notch 46 and which extend from said notch 46 following an arc of a circle having a radius of curvature R1, advantageously comprised between 0.5 and 1.5 cm or in a more empirical manner slightly greater than the turning radius of the pin 6 integral with the regulating organ 5 in relation to its axis of rotation X2. Said horns 44, 45 further comprise at their free end a cylindrical stud or finger 44e, 45e protruding perpendicularly to the median plane of the anchor 4, in which the plate 41, the arm 42 and the fork 43 extend. The studs could however also have another geometry. The horns 44, 45 thus form a guiding body for said pin 6 during the locking phases on the total angular amplitude in rotation of the regulating organ 5 if it is reduced and the oscillation frequency is important or almost the total additional arc in rotation of said regulating organ 5 if it is of the classical sprung balance type.

(21) In a complementary way to the horns 44, 45, the anti-overbanking device also comprises a circular flange 12 extending on both sides of the pin 6 on the regulating organ 5. Said flange 12 is centred on the rotation axis X2 of the regulating organ. Thus, the pin 6 being is integrated in said flange so that it moves, normally without contact, along an internal face of said horns during the locking phases of the escape wheel 2. The total length of the flange 12 is preferably substantially equal to the total distance between the studs 44e, 45e of said horns 44, 45.

(22) Thus, in case of impact on the mechanism 1 generating a movement of the anchor 4 prone to overbanking during the additional arc of the regulating organ, a stud 44e or 45e passes on the lower surface of the flange 12 but this does not entail a stoppage because the regulating organ 5 continues to rotate beyond this internal face of the flange 12 against the stud 44e, 45e as represented in FIGS. 16, 17 and in FIGS. 19, 20 on two distinct alternations. In addition, the returns (FIGS. 18, 21) of the flange 12 and of the pin 6 between the horns in a normal operational configuration are ensured by the free ends of the flange 12 which are advantageously bevelled in a vertical plane in order to yield the passage to said studs 44e, 45e to come back between the horns 44, 45 after having possibly tipped on the outside of the horns during the previous alternation. This arrangement and conformation of the horns 44, 45 and of the flange 12 therefore offer an optimal security against a possible overbanking, without disrupting negatively the operation of the escapement mechanism 1.

(23) FIGS. 4 at 15 show the different operational phases of the escapement mechanism of the invention on two successive alternations of the regulating organ 5, the respective rotation directions of the escape wheel 2, of the anchor 4 and of said regulating organ being represented by the arrows F1, F2, F3 on a first alternation respectively and the arrows F4, F5, F6 on a second alternation, respectively.

(24) FIG. 4 shows the mechanism 1 in an unlocking position. The pin 6 is in the notch 46 of the fork 43 of the anchor 4 and under the rotating action of the regulating organ 5 in the F3 direction, it leaves the rest against the pin 8 in the F2 direction, passing by the dead centre halfway (FIG. 1) to arrive (FIG. 5) in an indirect micro-impulse position via the entry-pallet 10. Then, the regulating organ 5 receives (FIG. 6) its direct impulse at pallet 9 by the escape wheel after which (FIG. 7) the fork drops (FIG. 8) against the pin 7 and the anchor 4 is in a locking position, a tooth 3 of the escape wheel 2 resting on the locking plane of the exit-pallet 11. The regulating organ 5 then travels along its additional arc (FIG. 9) and the anchor 4 undergoes a draw via its exit-pallet 11 against the pin 7.

(25) The regulating organ 5 then comes back in the opposite F6 direction towards the unlocking position (FIG. 10) on the second alternation, thus unlocking the anchor 4 of the pin 7, the anchor pivoting in the F5 direction. Then, passing by the dead centre (FIG. 11), it undergoes a second indirect micro-impulse at the exit-pallet 11 (FIG. 12) whereas the escape wheel is freed in rotation in the F4 direction, after which the anchor 4 drops on the pin 8 (FIG. 13), then reaching the second locking position (FIG. 14) where a tooth 3 of the escape wheel comes into abutment on the locking plane of the entry-pallet 10. The regulating organ 5 then continues its travel in the F6 direction by carrying out a coup perdu (vibration with no impulse) until the end of its second alternation to then come back in the F1 direction towards the unlocking position in FIG. 4.

(26) The escapement mechanism 1 of the invention therefore offers a direct escapement with a hybrid track having indirect micro-impulses and a slight draw as a Swiss anchor escapement in a direct escapement Robin type configuration without disrupting essentially its performance parameters and advantages but simplifying and increasing its reliability, while offering an optimal operational security.