Timepiece escapement mechanism

Abstract

Disclosed is an escapement mechanism (1) for a timepiece, designed to cooperate with an oscillator arranged to carry out oscillations, said mechanism (1) comprising: - a count wheel (7) arranged for step-wise forward rotation depending on the oscillations of the oscillator; - an impulse wheel (11) designed to be kinematically linked to a power source, said impulse wheel (11) being arranged to be periodically blocked and released under the control of the count wheel (7) and to supply impulses to the oscillator, characterized in that: - when said escapement mechanism (1) is operating, the count wheel (7) is continuously subjected to a torque; - and the count wheel (7) is arranged to rotate forward by one half-step of its toothing for every vibration of the oscillator.

Description

Technical field

[0001] The present invention relates to the field of watchmaking. It concerns, more particularly, an escapement mechanism. State of the art

[0002] The Swiss anchor escapement combined with a balance-spring oscillator has become the most commonly used regulating system today. It is simple, reliable, shock-resistant, and is well-mastered by watchmakers. However, it is not without its flaws, particularly in terms of energy efficiency and isochronism. Indeed, the interaction between the escape wheel and the anchor at each alternation of the balance wheel, as well as the resulting shocks, waste a lot of energy. In addition, pulling the anchor during disengagement also causes significant disruption to the balance wheel's oscillations. Indeed, using an anchor to both trigger an impulse and transmit it to the balance wheel is not optimal.

[0003] The detent escapement represents an improvement in efficiency and isochronism, the detent lever being actuated once per oscillation and the impulse being supplied directly by the escapement wheel to an impulse pallet rotating integrally with the balance. The balance is thus disturbed by the impulse once per oscillation instead of every alternation, and this disturbance is less significant than in the case of the Swiss lever. Indeed, the resistance provided by the detent lever is less than that of the lever because the impulse is supplied directly by the escapement wheel instead of being transmitted by a lever or similar, which results in lower energy consumption. The efficiency of the escapement and the power reserve of the movement are thus improved.

[0004] Document CH712052 describes a particular escapement with lost strokes. The balance wheel carries a unidirectional drive system which drives a counting wheel once per oscillation at a rate of one step per drive. This counting wheel is positioned by a jumper, and includes a cam which, once per n steps of the counting wheel, lifts a locking lever which holds an impulse wheel. The latter is thus free to pivot to give an impulse directly to the balance wheel and is relocked by the locking lever until the next actuation.

[0005] However, the presence of a unidirectional drive system mounted integral in rotation with the balance presents difficulties in terms of its development and with regard to the balancing of the balance. Indeed, this arrangement is little, if not not, compatible with conventional balances. Furthermore, the use of a jumper to position the counting wheel presents low shock resistance and is likely to be improved in terms of the resistance presented to the balance when driving said wheel.

[0006] Other prior art is formed by documents EP3070537, CH712052, EP2450755 and FR2110468.

[0007] The aim of the invention is therefore to provide an escapement for a timepiece in which the aforementioned defects are at least partially overcome. Disclosure of the invention

[0008] More specifically, the invention relates to an escapement mechanism for a timepiece, as defined by claim 1.

[0009] This escapement mechanism is, of course, intended to cooperate with an oscillator arranged to perform oscillations, such as for example a balance-spring oscillator, comprising an inertial mass (typically called a “balance”), arranged to perform rotational oscillations around its axis of rotation under the effect of a restoring force provided by an elastic element such as a balance spring.

[0010] The said mechanism includes: a counting wheel arranged to advance in rotation in discrete steps as a function of the oscillations of said oscillator; an impulse wheel intended to be in kinematic connection with a driving source such as a barrel storing a mainspring, said impulse wheel being arranged to be blocked and released periodically under the direct or indirect control of said counting wheel, that is to say as a function of its rotation and thus of its angular position and also to provide impulses to said oscillator. In other words, it is the rotational movements of the counting wheel which cause the release of the impulse wheel, and which thus trigger its periodic rotations.Said impulse wheel comprises teeth arranged to cooperate with an impulse pallet integral in rotation with a balance wheel which comprises said oscillator, said impulse wheel and said counting wheel each being pivoted on a respective axis of rotation, said axes being distinct from one another.

[0011] According to the invention, during operation of said system, the counting wheel is permanently subjected to a torque, for example under the effect of an elastic element which directly or indirectly exerts a force in the direction of the direction of rotation of the counting wheel at all times, and said counting wheel is arranged to advance in rotation at a rate of half a step of its teeth by alternation of said oscillator.

[0012] By these means, the disturbance of the oscillations of the oscillator is minimized for two reasons. Firstly, no jumper or pawl is necessary for the retention of the counting wheel since the latter is permanently subjected to a torque and can therefore be blocked by one or more pallets or the like. This torque ensures the rotational drive of the counting wheel, which is therefore not effected by a unidirectional drive system integral in rotation with the oscillator - the only effect of the oscillator being to release the counting wheel instead of driving it. It goes almost without saying that a release of the wheel requires less force than a direct drive, which disturbs the oscillator less. Furthermore, this reduced disturbance is divided between the two opposite alternations of the oscillator instead of being concentrated in one of the two.The disturbance is therefore divided rather symmetrically between the two alternations instead of representing a large disturbance due to driving one wheel in alternation out of two. The disturbance of the oscillator being thus minimized, its isochronism is improved, while maintaining the excellent power reserve that a lost-stroke escapement allows.

[0013] Advantageously, the mechanism comprises a first locking lever arranged to move between a first angular position and a second angular position during a first alternation of said oscillator, and to move between said second angular position and said first angular position during a second alternation of said oscillator, said locking lever being arranged to block the rotation of said counting wheel and to release the latter by half a step of its teeth during each of said movements of said first locking lever.

[0014] Advantageously, the mechanism further comprises a second locking lever arranged to lock and release said impulse wheel depending on the rotation of said counting wheel. For this purpose, said second locking lever may be arranged to release said impulse wheel at the rate of one step of its teeth for each n alternations of said oscillator, n being a number greater than two and preferably even, and even more preferably equal to four or six.

[0015] Advantageously, the second locking lever comprises a cam follower arranged to cooperate with at least one cam or at least one cam path integral in rotation with said counting wheel. The follower may be, for example, a lug, a pin, a fork or the like which may be integral with said counting wheel or may be attached to the latter or may be composed of an element integral in rotation with the counting wheel. It is possible to provide, for example, several separate cams, a continuous cam or a continuous cam path which cooperates with a cam follower of a shape appropriate for the shape chosen for the cam. It should be noted that the term "cam" is to be taken in the broad sense, a cam thus being able not only to have a conventional shape but also to have a particular toothing shape, pins or lugs, successions of pins or lugs forming a path, a spline etc.or any other element exerting a cam action.

[0016] Advantageously, said second locking lever comprises at least one pallet arranged to lock and release (when the time comes) said impulse wheel. This pallet may be made of stone or similar or may be made of the same material as said lever.

[0017] Advantageously, said second locking lever comprises a single pallet arranged to lock and release said impulse wheel, said second locking lever being arranged to be lifted by an actuating rocker in order to release said impulse wheel. This actuating rocker is arranged to move in translation between a retracted position in which said actuating rocker is out of the reach of an actuating pallet rotatably connected to said oscillator and an active position in which said actuating rocker is capable of cooperating with said actuating pallet to lift said second locking lever. The state of said actuating rocker, i.e. whether it is in an active position or a retracted position, is determined as a function of the angular position of said counting wheel.In this embodiment, the release of the impulse wheel is thus controlled by the counting wheel and triggered by the actuating paddle.

[0018] Advantageously, said actuating rocker is arranged to move between said active position and said retracted position under the effect of a control rocker carrying a cam follower arranged to cooperate with a cam path or cams integral in rotation with said counting wheel.

[0019] Advantageously, said torque, to which said counting wheel is subjected, is provided by means of an elastic element wound directly or indirectly by the impulse wheel. Said torque thus remains substantially constant during operation of the mechanism, the elastic element being recharged each time the impulse wheel moves angularly.

[0020] Advantageously, said elastic element is part of a refill assembly comprising a wheel in kinematic connection with said counting wheel. A first end of said elastic element can thus be fixed to said wheel and a second end of said elastic element being integral in rotation with a refill wheel arranged to be driven in rotation by a toothing which said impulse wheel comprises.

[0021] Advantageously, said refill wheel is arranged to be retained by a retention lever arranged to block a rotation of said refill wheel in a first direction and to be lifted by a tooth of said refill wheel when the latter pivots in a second direction, opposite to said first direction.

[0022] Advantageously, said retention lever is arranged to cooperate with a plurality of stops provided on said impulse wheel, said stops being arranged to prevent said retention lever from being released, except when said recharging wheel is being driven by said impulse wheel. The retention lever is thus protected from shocks and no untimely triggering of the impulse wheel is possible.

[0023] Advantageously, said impulse wheel and said recharging wheel each comprise a plurality of teeth distributed between at least two different planes, each tooth of a first plane being angularly located between two angularly adjacent teeth of the other plane(s).

[0024] Advantageously, a first end of said elastic element is integral in rotation with said impulse wheel and a second end of said elastic element is integral in rotation with a wheel kinematically connected to said counting wheel. This construction is particularly very compact and does not require any separate refill wheel.

[0025] Advantageously, said second locking lever comprises a single locking paddle arranged to lock the impulse wheel as well as a cam follower arranged to cooperate with at least one cam that said counting wheel comprises, said counting wheel comprising a plurality of stops arranged to prevent said second locking lever from releasing said impulse wheel except when said cam follower is being actuated by said at least one cam. This arrangement of stops protects the second locking lever from shocks, preventing it from lifting except when it is actuated by said at least one cam.

[0026] Said mechanism can be integrated into a timepiece movement comprising a mechanism according to one of the preceding claims as well as an oscillator arranged to cooperate with said mechanism, this movement being able to be integrated into a timepiece. Brief description of the drawings

[0027] Other details of the invention will appear more clearly on reading the following description, given with reference to the appended drawings in which: THE figures 1 to 10 are isometric representations of a first embodiment of an escapement according to the invention, during several of its operating phases; The figures 11 to 13 are isometric representations from different angles of a second embodiment of an escapement according to the invention, just before the release of the counting wheel; The figures 14 to 21 are isometric representations from different angles of a third embodiment of an escapement according to the invention, in several operating states; and The figure 22 is an isometric representation of the actuating rocker of the third embodiment. Embodiments of the invention

[0028] There figure 1illustrates a first embodiment of an escapement mechanism 1 according to the invention.

[0029] The escapement 1 cooperates with a sprung balance oscillator, of which only the plate 3 has been shown so as not to overload the drawings and whose axis of rotation has been represented by a vertical chain line. This plate 3, as well as the sprung balance to which it is integral in rotation, can be of conventional shape but other known variants (for example balances without rims, high frequency or similar) are also possible. The plate comprises a pin 3a as well as an impulse pallet 3b, which can alternatively be mounted directly on the balance. These components each have a conventional shape, the pin 3a serving to pivot a first blocking lever 5 by means of a fork 5a which the latter comprises.It is noted that it is also possible for the plate 3 to be composed of several parts, for example in order to be able to adjust the angular position of one or the other of the pin 3a and the impulse pallet 3b relative to the plate 3, and this without influencing the position of the other.

[0030] Said fork 5a is well known in the context of the Swiss lever escapement. It cooperates with the pin 3a once per alternation in order to move the first blocking lever 5 from a first stable angular position (illustrated on the figure 1 ), towards a second stable angular position (illustrated on the figure 2 ) during an alternation of the pendulum in a first direction (clockwise according to the orientation shown on the figure 1 ) and in the other direction when the pendulum alternates in the other direction (counterclockwise depending on the orientation of the figure 1). The extreme angular positions of the first locking lever are defined by conventional stops 17a, arranged on either side of an arm of said lever 5.

[0031] The first locking lever 5 comprises a pair of pallets 5b, 5c, which cooperate with a counting wheel 7, which is pivoted about a corresponding axis of rotation 7z and which is subjected to a torque tending to drive it in the clockwise direction (according to the orientation of the figure 1 ) when the escapement is operating. When the first locking lever 5 is in its first angular position (see the figure 1), the output pallet 5c blocks a tooth of the counting wheel 7, and, when said lever 5 is in its second angular position, the input pallet 5b in turn blocks another tooth of the counting wheel 7. In doing so, during each alternation of the balance, the counting wheel 7 advances at the rate of half a step of its teeth, a whole step being taken during a complete oscillation, which by definition consists of two successive alternations. Although the pallets 5a, 5b have been represented here as stone pallets fixed to the first blocking lever 5, they can alternatively be made in one piece with the latter. Indeed, the term "pallet" rather means a functional element integral with the lever 5 instead of a separate element attached to the latter, which also applies to any pallet mentioned in the present text.

[0032] In order to provide torque to ensure the advancement of the counting wheel 7, the escapement mechanism 1 further comprises a recharging assembly 9, which comprises a wheel 9a in kinematic connection with the counting wheel 7 by means of a pinion 7a integral in rotation with the latter. Coaxial with said wheel 9a are a recharging wheel 9c as well as an elastic element 9b, one of its ends of which is fixed to said wheel 9a and the other end of which is fixed to the recharging wheel 9c. The wheel 9a can pivot relative to the recharging wheel 9c, and, when the mechanism 1 is at rest, the elastic element is subjected to a prestress. The counting wheel 7 is thus subjected to a torque at all times, this torque being provided by the elastic element 9b and tending to drive the counting wheel 7 in its direction of rotation.It is noted that the elastic element 9b as shown is a spiral spring, but other shapes are also possible, such as, for example, a leaf spring or any other elastic element known to those skilled in the art.

[0033] In this embodiment, the refill wheel 9c is driven by the impulse wheel 11, as explained below, and is prevented from pivoting in the wrong direction by a retention lever 13, the extreme angular positions of which are defined by ad hoc stops 17b. This retention lever 13 comprises a locking pallet 13a which, at rest, cooperates with a right flank of a tooth that the refill wheel 9c comprises. When the refill wheel 9a is pivoted counterclockwise (relative to the figure 1 ) by a tooth of the impulse wheel 11, the locking pallet 13a is lifted by the curved flank of the next tooth, as described below.

[0034] The impulse wheel 11 is pivoted around its own rotation axis 11z, and is driven by a driving source such as a barrel, the force arriving at its pinion 11a which is integral with it in rotation. This pinion 11a thus serves as a torque input for the mechanism 1.

[0035] The impulse wheel 11 comprises a plurality of impulse teeth 11b, arranged in two rows on two different levels of the impulse wheel 11, the teeth of one row being angularly interposed between those of the other with constant angular separations. These teeth cooperate with the impulse pallet 3b, which has a sufficient height to cooperate with the two rows. It is also noted that an arrangement of the teeth 11b in a single plane is also possible, but the chosen configuration makes it possible to prevent angularly adjacent teeth from unintentionally coming into contact with other elements, for example, when driving the refill wheel 9c. Furthermore, the teeth can also be arranged in more than two rows on more than two different levels, the teeth of the refill wheel 9c being of course arranged to cooperate correctly with the rows of teeth of the impulse wheel.

[0036] The impulse wheel 11 is locked by a second locking lever 15, which comprises a pair of pallets 15a and 15b arranged to lock the teeth 11b of the impulse wheel 11 and to release them one by one when the locking lever 15 is moved from one of its stable angular positions to the other, in a conventional manner. In this embodiment, the second locking lever 15 therefore takes the form of an anchor, and the same comments, as made above in the context of pallets 5b and 5c, apply to pallets 15a and 15b.

[0037] The angular displacement of the second locking lever 15 to effect the release of the impulse wheel 11 is controlled by the counting wheel 7, which has a cam track 7b. The latter has smaller radius sections 7c and larger radius sections 7d, regularly distributed angularly. A cam follower 15c, in the form of a pin, is carried by an arm 15d of the second locking lever 15 and takes place in this cam track 7b. The latter is shaped to control the second locking lever 15 in order to release the impulse wheel once per n oscillations of the balance during the transition from a smaller radius section 7c to a larger radius section 7d, and vice versa. In the illustrated embodiment, n is three and, consequently, the radius of the cam track changes every three teeth of the counting wheel, but it can in principle change more or less frequently.As a result, after three teeth have passed (i.e. following 6 vibrations of the balance wheel), the second locking lever 15 changes its angular position from one of its extreme positions to the other and one of the teeth 11b of the impulse wheel 11 cooperates with the impulse pallet 3b in order to transmit an impulse to the oscillator. Alternatively, the counting wheel 7 may comprise a conventional cam, a cam follower carried by the second locking lever 15 being held in contact with said cam by an ad hoc elastic element. Alternatively, the counting wheel 7 may comprise a constant radius cam, the second locking lever 15 having a fork whose two arms follow said cam.

[0038] Before being locked again by one of the pallets 15a, 15b of the second locking lever 15, one of the teeth 11b of the impulse wheel cooperates with a tooth of the refill wheel 9c in order to drive it at a rate of one pitch of its toothing, the latter also comprising two rows of teeth arranged in two different planes in order to be able to cooperate with the two-row toothing of the impulse wheel. As a result, the retention lever 13 is lifted by the curved flank of a tooth, then falls back into the trajectory of the next tooth under the effect of a return spring 13b in order to relock the refill wheel 9c.

[0039] In order to protect the retention lever 13 from impacts, it further comprises a safety pallet 13c, which takes place inside the impulse wheel 11. The latter comprises a plurality of stops 11c extending projecting from its rim in a direction parallel to the axis of rotation of the wheel 11. These stops 11c serve to prevent the retention lever 13 from being lifted except when the refill wheel 9c is being driven. For this purpose, the stops 11c are arranged to block the safety pallet 13c, and gaps 11d separating said stops 11c are positioned to allow the passage of the safety pallet 13c exclusively at the time of driving the refill wheel 9c. As a result, the retention lever 13 is prevented from moving angularly in an untimely manner, for example following an impact.Even if the stops 11c and the gaps 11d have been illustrated as being integral with the impulse wheel 11, they can also be defined by one (or even several) element(s) added to the latter.

[0040] The construction and general principle of operation of the escapement of the figure 1 having been described, the phases of its operation will now be explained in more detail. Subsequently, only the reference signs mentioned in the text in the context of a particular figure will be reproduced on the figure in question.

[0041] There figure 1 illustrates the positions of the components during a first alternation of the oscillator in the direction indicated. The counting wheel 7 is blocked by the output pallet 5c of the first blocking lever 5, which is in its first angular position. The plate 3 is pivoting clockwise (relative to the figure 1) and the pin 3a has just entered the fork 5a of the first locking lever 5. The pin 15c of the second locking lever 15 is located at the beginning of a smaller radius section of the cam path 7b and the impulse wheel 11 is blocked by the output pallet 15b of the second locking lever 15.

[0042] On the figure 2 , the plate 3 has pivoted to the point where the first locking lever 5 has arrived in its second angular position after pivoting counterclockwise (relative to the figure 2 ). This change in angular position released the counting wheel, which pivoted half a step of its teeth under the effect of the elastic element 9b, and was blocked again by the input pallet 5b of the first blocking lever 5. The pin 15c of the second blocking lever remains in the same lower radius section of the cam path 7b, and the rest of the mechanism thus remains in the same state.

[0043] There figure 3 illustrates the situation during the next alternation, counterclockwise (relative to the figure 3 ), after actuation of the first locking lever 5 by the pin 3a. Again, the change in angular position of the first locking lever 5 from its second angular position to its first angular position releases the counting wheel 7 by another half step under the effect of the elastic element 9b, the counting wheel 7 being locked again by the output pallet 5c of the first locking lever 5. In doing so, the pin 15c of the second locking lever remains in the same smaller radius section of the cam path 7b, and the rest of the mechanism thus remains in the same state.

[0044] This cycle continues until pin 15c reaches the end of the lower radius section of cam track 7b, which occurs at the sixth alternation counted from the condition shown in figure 1 .

[0045] The moment of release of the counting wheel 7 during the sixth alternation is illustrated in the figure 4 .

[0046] The counting wheel 7 has pivoted and the pin 15c of the second locking lever 15 has just moved up to the next section of the cam path 7b, with a larger radius 7d.

[0047] This section transition pivoted the second release lever 15, which lifted its output vane and released the impulse wheel.

[0048] On the Figure 5 , the pin 15c has completed its ascent in the upper radius section 7d and the output pallet 5c of the first locking lever 5 has blocked the next tooth of the counting wheel 7, which has had the effect of stopping it.

[0049] At the same time, a tooth of the impulse wheel 11 catches up with the impulse pallet 3b and begins to give an impulse to the latter.

[0050] There figure 6illustrates the state of the components at the end of the impulse, just before the contact between the impulse pallet 3b and the corresponding tooth of the impulse wheel 11 is broken. At the same time, another tooth of the impulse wheel comes into contact with the right face of a tooth of the refill wheel 9c, as indicated by the corresponding oval.

[0051] There figure 7 illustrates the state of the components when recharging the recharging wheel 9c. The tooth of the impulse wheel 11, which interacts at this moment with the recharging wheel 9c, rotates the latter counterclockwise (relative to the figure 7), which raises the elastic element 9b. During this drive, the curved face of another tooth of the recharging wheel 9c comes into contact with the locking pallet 13a. At this precise moment, the safety pallet 13c is opposite a gap 11d between two stops 11c of the impulse wheel 11. The oscillator continues its path and no longer concerns us until the next alternation.

[0052] There figure 8 illustrates the state of the components a few moments after that described on the figure 7 . The locking paddle 13a has reached the top of the tooth of the refill wheel 9c and the safety paddle 13c has retracted into the gap 11d, which allows sufficient angular movement on the part of the retention lever 13 to carry out this operation.

[0053] There figure 9illustrates the situation once the locking pallet 13a has passed the top of the tooth of the refill wheel 9c. The locking pallet 13a as well as the retention lever 13, with which it is integral, fall back into their initial position under the effect of their return spring 13b. In doing so, the safety pallet 13c leaves the gap 11d and the locking pallet 13a blocks the right face of the next tooth of the refill wheel 9c, stopping it again. The impulse wheel 11 remains free for the moment, and therefore continues to pivot clockwise (relative to the figure 9 ).

[0054] There figure 10 illustrates the end of this phase of rotation of the impulse wheel 11, one of its teeth having come into contact with the input pallet 15a of the second locking lever 15.

[0055] Six oscillator alternations later, the same pulse and recharge cycle is repeated, with the second locking lever 15 switching from its second angular position, as shown in Fig. 10, to its first angular position, as shown in Fig. figure 1 , when the cam follower 15c makes the transition from the upper radius section to the lower radius section of the cam path 7b. The system is thus returned to its starting position and the entire cycle is repeated.

[0056] It is thus clear that, by modifying the shape of the cam path 7b, the manufacturer can modify the number of lost strokes of the escapement. He can even arrange the escapement to give impulses asymmetrically, that is to say that the number of alternations counted can vary, for example according to a sequence of 4 alternations, then 6 alternations, then 4 alternations, then 6 alternations, by acting on the respective angular lengths of the lower radius sections 7c and upper radius sections 7d.

[0057] THE figures 11 to 13 illustrate a second embodiment of an escapement mechanism 1 according to the invention, from several angles. The operating principle of this embodiment remains substantially similar to that of the embodiment of figures 1 to 10 and therefore only the structural and functional differences will be described subsequently.

[0058] The second locking lever 15 of this embodiment takes the form of a detent instead of an anchor and, for this purpose, comprises only one locking pallet 15a. The latter is held in engagement with the impulse wheel 11 by means of an elastic return element 15f, one end of which is fixed to a frame element (not shown), the other exerting a force on the lever 15. The extreme angular positions of the latter are again defined by ad hoc stops 17c. The impulse wheel 11, which has only a single row of teeth arranged in a single plane, is arranged to pivot counterclockwise (relative to the figure 11 ), but modifications to rotate it the other way are within the reach of those skilled in the art.

[0059] The second locking lever 15 is actuated by a plurality of cams 7f, integral in rotation with the counting wheel 7, which are arranged to lift the cam follower 15c, which is again carried by an arm 15d of the second locking lever 15, and is formed as an extension of the latter in the direction of the counting wheel 7. Once every n alternations (n ​​being 6 here), one of the cams 7f, which here have the shape of a plurality of individual teeth, lifts the second locking lever 15, which lets a tooth of the impulse wheel 11 escape. The second locking lever 15 immediately falls back under the effect of its elastic element 15f and the rotation of the impulse wheel 11, at a rate of one step, provides an impulse to the impulse pallet 3b in the clockwise direction (relative to the figure 11 ), by means of another of its teeth. Then, the pallet 15a relocks the impulse wheel 11.

[0060] In order to ensure that the second locking lever 15 is not raised inadvertently following an impact, the counting wheel 7 is provided with a plurality of stops 7g extending projecting from the rim of the counting wheel 7, these stops 7g being separated by gaps 7h. Again, these stops 7g extend parallel to the axis of rotation of the counting wheel 7. When the cam follower 15c is not opposite a gap 7h, it is blocked by one of the stops 7g and the impulse wheel 11 cannot thus be released. On the other hand, when the cam follower 15c cooperates with one of the cams 7f of the counting wheel 7 to move the second locking lever 15 in order to release the impulse wheel 11, said follower 15c is opposite a gap 7h between two adjacent stops 7g, as shown more clearly in figure 12. As a result, the cam follower 15c is not blocked by the stops 7g and the second locking lever 15 is free to pivot sufficiently to release the impulse wheel 11 and thus trigger an impulse.

[0061] In this embodiment, the recharging assembly 9 is simplified and mounted coaxially with the impulse wheel. For this purpose, the inner end of the elastic element 9b is rotationally fixed to the impulse wheel 11, and no recharging wheel is present. Consequently, each time the impulse wheel 11 is released by the second locking lever 15, the elastic element 9b is simply raised by the rotation of the axis of the latter.

[0062] The operating cycle of this embodiment therefore follows in a similar manner to that of the embodiment of the figures 1 to 10 , mutatis mutandis.

[0063] THE figures 14 to 21further illustrate an embodiment of an escapement mechanism 1 according to the invention. Again, not all of the reference signs appear in each figure. This embodiment will be explained with reference to its differences from that of figures 11 to 13 , with which it has the greatest similarities, in particular in view of the fact that the impulse wheel 11 is coaxial with the wheel 9a of the reloading assembly 9 and that the second locking lever 15 again takes the form of a trigger having a single pallet 15a. The return force of the second locking lever 15 is provided by a leaf spring 15f, but other forms are possible.

[0064] However, in this embodiment the second locking lever 15 is not controlled directly by the cam path 7b integral in rotation with the counting wheel 7, but indirectly by means of an actuating rocker 19, mounted in translation and in pivoting on a frame element not shown. This pivoting will be described below in the context of the figure 17 and is limited by conventional stops 17a.

[0065] The actuating rocker 19 has an end 19a, which is connected to the main body of said rocker 19 by means of a blade 19f which has a certain flexibility, said end 19a being arranged to cooperate with an actuating pallet 3d secured to the plate 3. The latter can take the form of a conventional pallet, a pin, a finger or any equivalent form. It can be integral with the plate 3 or can be an element attached to the latter. In the state shown in the figure 14, just before the first release of the counting wheel 7 at the start of an operating cycle, the actuating rocker 19 is in an inactive position and its end 19a is out of reach of the actuating paddle 3d and therefore has no effect during the oscillations of the oscillator. It is also noted that said end 19a is in a different plane from that of the impulse wheel 11, and this point will be returned to below.

[0066] The translation of the actuating rocker 19 is controlled by a control rocker 21, pivotally mounted on a frame element (not shown). A first end of this rocker 21 carries a cam follower 21a which takes place in said cam path 7b, the other end 21b being arranged to move the actuating rocker 19 in translation in a direction substantially following the main axis of the latter. For this purpose, the control rocker 21 carries a stud 21c which takes place with play in a slot 19d in the actuating rocker, this slot 19d extending substantially perpendicular to said direction and to the main axis 19g of said rocker 19 (see figure 22 ). Other configurations are of course possible. A 21d screw, visible on the figures 14 And 20 exclusively, ensures that the control rocker 21 and the actuating rocker do not separate from each other.

[0067] The cam path 7b is shaped such that, during the four following alternations of the balance, the follower 21a remains in a section with a larger radius 7d which said cam path 7b comprises. In doing so, the actuating rocker 19 remains in its retracted position and its end does not cooperate with the actuating pallet.

[0068] There figure 15 illustrates the situation just before the release of the counting wheel 7 during the fifth alternation, at which time the cam follower 21a has reached the end of a larger radius section 7d of the cam path 7b.

[0069] Tray 3 continues to rotate counterclockwise (relative to the figure 15 ), lifts the first locking lever 5 and releases the counting wheel 7, which advances at a rate of half a step under the effect of the elastic element 9b as discussed above in the context of the other embodiments.

[0070] THE figures 16 and 17illustrate in two views the state of the mechanism towards the end of said fifth alternation, the cam follower 21a having followed the cam path 7b to the bottom of a section with a lower radius 7c. In doing so, the control rocker 21 has pivoted clockwise (according to the orientation of the figure 16 ), which has caused a translation of the actuating rocker 19 towards the plate 3, as indicated by the arrows. The actuating paddle 3d has just lifted the end 19a of said rocker 19, without effect on the angular position of the body of the latter, thanks to the elasticity of the blade 19f which allows the end 19a to move away when the actuating paddle 3d circulates in the counterclockwise direction (also according to the orientation of the figure 16 ). For the rest, note that this spacing of the end 19a can occur in different directions, depending on the configuration and shape of the components of the system. “actuating paddle - actuating rocker - blade”,in particular parallel to the axis of rotation of the plate, radially or a combination of the two. Modifications to the mechanism to allow spacings in these other directions are within the reach of those skilled in the art and therefore do not need to be described in detail here.

[0071] In order for said translation to be substantially rectilinear, the actuating rocker 19 is guided by its two slots 19b, 19c, which extend substantially parallel to the main axis 19g (see figure 20) of the actuating rocker 19. The first slot 19b houses a pin 15h which is integral with the second locking lever 15 at a point remote from its axis of rotation. The second slot 19c contains a stud 23 which is integral in translation with a frame element and which serves as a pivot axis for the second locking lever 15. Consequently, when the control rocker 21 pivots as described above, the actuating lever 19 is moved in translation such that its end 19a enters the range of the actuating paddle 3d. The actuating rocker 19 is thus in an active position, in which it is capable of cooperating with the actuating paddle 3d to trigger the impulse as will be described later.

[0072] The current alternation continues, with tray 3 continuing its path counterclockwise (relative to the figure 16 ).

[0073] In the next alternation, that is, the sixth from the situation illustrated in the figure 14 , the 3d actuation paddle, moving clockwise (relative to the figure 16 ) comes into contact with the end 19a of the actuating rocker 19, as illustrated in the figure 18 The interaction between the actuating paddle 3d and the actuating rocker 19 takes place before the pin 3a causes the angular position of the first locking lever 5 to change. Since the end 19a is connected to the main body of the actuating rocker 19 via the flexible blade 19f, the rocker 19 also comprises a substantially rigid stop 19h against which the end 19a and / or the blade 19f abuts so that the actuating paddle 3d can act on the angular position of the entire actuating rocker 19 when it moves clockwise relative to the figure 16(but not the other way around as mentioned above).

[0074] As illustrated in the figure 19 , the actuating paddle 3d lifts the end 19a of the actuating rocker 19, which lifts the second locking lever 15 thanks to the interaction between the first slot 19b and the pin 15h (see the figure 17 ).

[0075] The impulse wheel 11 is thus released, the impulse is triggered and one of the teeth of the impulse wheel 11 gives an impulse to the impulse vane 3b in a counterclockwise direction (relative to the figure 19 ) under the effect of the torque coming from the driving source (not shown) as described above in the context of the other embodiments.

[0076] When the actuating paddle 3d passes the end 19a and consequently releases the actuating rocker 19, the latter and the second locking lever 15 fall back under the effect of the elastic element 15f, the locking paddle 15a stopping and locking the next tooth of the impulse wheel. This situation is illustrated in the figure 20 .

[0077] Since the control rocker 21 is still in the position of figures 16 to 19 , the actuating rocker 19 is always in its active position. In order to prevent the impulse vane 3b from hitting the end 19a of said rocker 19, which would stop the oscillator, said vane 3b has a cutout 3f which prevents any contact between these two elements, the interaction between the impulse wheel 11 and said vane 3b takes place in a plane different from that of said cutout 3f.

[0078] Then, the pin 3a drives the first locking lever 5 in an anticlockwise direction (relative to the figure 20 ), which releases and advances the counting wheel 7 by half a step, the cam follower 21a moves up to the next higher radius section 7d. In doing so, the control rocker 21 pivots counterclockwise (relative to the figure 20 ), thus removing the actuating rocker 19 so that its end 19a is no longer within the range of the actuating paddle 3d and the mechanism is thus in the situation illustrated in the figure 14 The operating cycle can then begin again.

[0079] By these means, again the counting wheel 7 controls the periodic release of the impulse wheel 11, even if the latter is triggered by the actuating paddle 3d. In other words, the position of the actuating rocker 19 is controlled by the counting wheel 7 via the control rocker 21, the active position of the actuating rocker 19 authorizing the triggering of the impulse.

[0080] In order to prevent the actuating lever 19 from being displaced in the event of an impact and from starting to rotate and / or translate - when it should not be in the passage zone of the actuating pallet 3d (between the 6th and the 4th following alternation) - stops 17a are provided in order to prevent untimely rotation of this lever: in fact, this would have the effect of lifting the 2nd locking lever 15 and releasing the impulse wheel 11 at an undesired moment.

[0081] Furthermore, to prevent this rocker 19 from moving in translation in said zone, the cam follower 21a, located in the cam path 7b (therefore having an anti-shock effect), is prevented from moving unexpectedly.

[0082] However, a cam arrangement similar to that of the embodiment of the figures 11 to 13 is also possible, provided there is appropriate shock-proofing.

[0083] Furthermore, between the 5th and 6th vibrations, so that the impulse wheel 11 is not released unintentionally in the event of an impact, the second locking lever 15 carries a finger 15g, arranged to abut against the periphery of the plate 3 when this second locking lever 15 is not allowed to rise. In order to allow the release of the impulse wheel 11, exclusively when the plate 3 is in the correct orientation, a notch 3f is provided in the plate 3. When the finger 15g is opposite said notch 3f (see figures 18 and 19 ), the second locking lever 15 is allowed to rise in order to release the impulse wheel 11 in the event that an interaction between the actuating paddle 3d and the actuating rocker 19 takes place.

[0084] Furthermore, other arrangements for guiding the actuating rocker 19 are of course possible, and the recharging assembly 9 of the embodiment of the figures 1 to 10 can also be applied in this embodiment.

[0085] The technical effects obtained by these constructions are as follows.

[0086] With regard to the first locking lever 5, the forces generated during its interaction with the pin 3a are minimal and are generated in a "symmetrical" manner. As a result, the disturbance of the oscillator is minimized and is divided between the alternations in the two directions of rotation instead of being concentrated in a single, more significant disturbance, once per oscillation.

[0087] The fact that the counting wheel 7 is subjected to a torque via the elastic element 9b has the consequence of avoiding any use of a jumper or the like to retain the counting wheel 7, which is simply blocked by the pallets of the first blocking lever 5 in a manner similar to a conventional anchor. For this purpose, a pulling angle can be provided for the resting surfaces of the pallets 5b and 5c, in a known manner. As a result, the oscillator does not itself drive the counting wheel 7, as is the case in CH712052. The oscillator simply triggers the rotation of the counting wheel 7 under the effect of the elastic element 9b. It goes without saying that such a triggering requires significantly less force than a direct drive overcoming the effect of a jumper, and consequently the disturbances of the oscillator are minimized.

[0088] Since the counting wheel 7 is driven by the elastic element 9b which is recharged at each step of the impulse wheel 11, said torque remains relatively constant and the resistance to the release of the first blocking lever 5 also remains substantially constant and does not vary according to the winding state of the barrel spring of the movement in which the escapement 1 is integrated.

[0089] Since the efficiency of this escapement 1 is very good, the number of lost strokes of escapement 1 can be increased, that is to say by providing an impulse only once every two or three (or even more) oscillations, the power reserve of the movement being thus improved compared to a conventional escapement since the impulse wheel 11 pivots less frequently. In addition, the disturbances of the oscillator due to the impulses are also reduced by decreasing the impulse frequency, which increases the isochronism of the oscillator.

[0090] It is also noted that the escapement mechanism 1 according to the invention, in all its variants, is compatible with integration into a tourbillon system with one, two, or three axes of rotation.

[0091] As regards the materials that can be used to produce the various components of the escapement mechanism 1, these can be composed of “traditional” materials, such as metals and alloys (steel, brass, nickel, nickel phosphorus, etc.), silicon-based materials (Si, SiOx, SiCx, SiNx, etc.) in monocrystalline, polycrystalline or amorphous form, diamond, ruby, sapphire, corundum, glasses, ceramics, glass-ceramics, polymers, composites, etc. The components can be machined conventionally, but can also be produced using additive technologies such as LIGA, sintering, 3D printing, etc., in various materials (for example, epoxy or other polymer material), depending on the material. In addition, coatings of different materials can be provided at stressed locations in order to increase their strength, reduce friction, or similar (diamond, etc.).

[0092] Although the invention has been particularly shown and described with reference to particular embodiments, other variations are possible without departing from the scope of the invention as defined in the claims.

[0093] For example, considering the mode of realization of the figures 11 to 13 , the second locking lever 15 can take the form of an anchor, like that of the figures 1 to 10 , the 7f cams being replaced by a conventional cam or a cam track like that of the figures 1 to 10 . The use of a cam track for the actuation of a second locking lever having the shape of an anchor will make it possible to eliminate the 7g stops on the counting wheel 7 since such an arrangement is shock resistant.

[0094] Alternatively, the person skilled in the art may modify the arrangement of the figures 1 to 10 such that the second locking lever 15 has only one locking paddle and thus acts as a trigger.

[0095] Furthermore, in the case where the escapement mechanism 1 is incorporated in a clock and is not subject to shocks, the stops 11c resp. 7g can be omitted, the safety pallet 13c of the embodiment of the figures 1-10 which can also be deleted.

Claims

1. Escapement mechanism (1) for a timepiece, intended to cooperate with an oscillator arranged to perform oscillations, said mechanism (1) comprising : - a counting wheel (7) arranged to advance in rotation by steps as a function of the oscillations of said oscillator ; - an impulse wheel (11) intended to be kinematically linked to a drive source, said impulse wheel (11) being arranged to be blocked and released periodically under the control of said counting wheel (7), and to supply pulses to said oscillator, said impulse wheel (11) comprising teeth (11b) arranged to cooperate with an impulse pallet (3b) rotationally integrated with a balance wheel comprised by said oscillator; in which : - said impulse wheel (11) and said counting wheel (7) are each pivoted on a respective axis of rotation (11z, 7z), said axes (11z, 7z) being distinct from one another ; - during operation of said escapement mechanism (1), said counting wheel (7) is permanently subjected to a torque; and - said counting wheel (7) is arranged to advance in rotation at a rate of half a tooth pitch per vibration of said oscillator.

2. Mechanism (1) according to claim 1, further comprising a first blocking lever (5) arranged to move between a first angular position and a second angular position during a first vibration of said oscillator, and to move between said second angular position and said first angular position during a second vibration of said oscillator, said blocking lever (5) being arranged to block the rotation of said counting wheel (7) and to release the latter at a rate of half a pitch of its teeth during each of said movements of said first blocking lever (5).

3. Mechanism (1) according to the preceding claim, further comprising a second blocking lever (15) arranged to block and release said impulse wheel (11) as a function of the rotation of said counting wheel (7).

4. Mechanism (1) according to claim 3, wherein said second blocking lever (15) is arranged to release said impulse wheel (11) at a rate of one step for each n vibrations of said oscillator, n being a number greater than two.

5. Mechanism (1) according to one of claims 3 and 4, wherein said second blocking lever (15) comprises a cam follower (15c) arranged to cooperate with at least one cam (7f), or at least one cam track (7b), integral in rotation with said counting wheel (7).

6. Mechanism (1) according to one of claims 3-5, wherein said second blocking lever (15) comprises at least one pallet (15a, 15b) arranged to block and release said impulse wheel (11).

7. Mechanism (1) according to one of claims 3 and 4, wherein said second blocking lever (15) comprises a single pallet (15a) arranged to block and release said impulse wheel (11), said second blocking lever (15) being arranged to be lifted by an actuation lever (19) in order to release said impulse wheel (11), said actuation lever (19) being arranged to move in translation between a retracted position in which said actuation lever (19) is out of reach of an actuating pallet (3d) integral in rotation with said oscillator, and an active position in which said actuation lever (19) is able to cooperate with said actuating pallet (3d) to lift said second blocking lever (15), the state of said actuation lever (19) being determined as a function of the angular position of said counting wheel (7).

8. Mechanism (1) according to the preceding claim, in which said actuation lever (19) is arranged to move between said active position and said retracted position under the effect of a control lever carrying a cam follower arranged to cooperate with a cam track or cams integral in rotation with said counting wheel (7).

9. Mechanism (1) according to one of the preceding claims, wherein said torque, to which said counting wheel (7) is subjected, is provided via an elastic element (9b) arranged to be armed by said impulse wheel (11).

10. Mechanism (1) according to the preceding claim, wherein said elastic element (9b) forms part of a recharging assembly (9) comprising a wheel (9a) in kinematic connection with said counting wheel (7).

11. Mechanism (1) according to the preceding claim, wherein a first end of said elastic element (9b) is fixed to said wheel (9a) and a second end of said elastic element (9b) is integral in rotation with a recharging wheel (9c) arranged to be driven in rotation by a toothing comprised by said impulse wheel (11).

12. Mechanism (1) according to the preceding claim, wherein said recharging wheel (9c) is arranged to be retained by a retention lever (13) arranged to block rotation of said recharging wheel (9c) in a first direction and to be lifted by a tooth of said recharging wheel (9c) when this latter rotates in a second direction opposite to said first direction.

13. Mechanism (1) according to the preceding claim, wherein said retention lever (13) is arranged to cooperate with a plurality of abutments (11c) provided on said impulse wheel (11), said abutments (11c) being arranged to prevent said retention lever (13) from disengaging, except when said recharging wheel (9c) is being driven by said impulse wheel (11).

14. Mechanism (1) according to the preceding claim, wherein said impulse wheel (11) as well as said recharging wheel (9c) each comprise a plurality of teeth distributed between at least two different planes.

15. Mechanism (1) according to claim 9, wherein a first end of said elastic element (9b) is integral in rotation with said impulse wheel (11), a second end of said elastic element being integral in rotation with a wheel (9a) in kinematic connection with said counting wheel (7).

16. Mechanism (1) according to claims 6 and 15, wherein said second blocking lever (15) comprises a single blocking pallet (15a) arranged to block the impulse wheel as well as a cam follower (15c) arranged to cooperate with at least one cam (7f) comprised by said counting wheel (7), said counting wheel (7) comprising a plurality of stops (7g) arranged to prevent said second blocking lever (15) from releasing said impulse wheel (11), except when said cam follower (15c) is being actuated by said at least one cam (7f).

17. Timepiece movement comprising a mechanism (1) according to one of the preceding claims and an oscillator arranged to cooperate with said mechanism.

18. Timepiece comprising a movement according to the preceding claim.

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