CH717785B1 - Natural escapement for a clock movement and clock movement comprising such an escapement. - Google Patents

Abstract

The invention relates to a natural escapement (1) for a watch movement carrying out a succession of operating cycles each consisting of a first and a second alternation of a balance wheel (16) which comprises a balance wheel (18) as well as a balance plate (22) fitted on an axis (20) of the balance wheel (18), this natural escapement (1) comprising a first escapement wheel (8) arranged to be driven by a mobile second (2), this first escapement wheel (8) in turn driving a second escapement wheel (12) arranged in the same plane as the first escapement wheel (8), an anchor (30) capable of pivot around an anchor rod (32), this anchor (30) comprising means for temporarily blocking the first escape wheel (8) during the first alternation, and means for temporarily blocking the second escape wheel escapement (12) during the second alternation, the anchor rod (32) being located outside an angle (α) less than 180° and delimited by two straight lines which pass through the axis (20) of the balance wheel (18) and through a pivot axis (6) of the first escapement wheel (8) for one, and by the axis (20) of the balance wheel (18) and by a pivot axis (14) of the second escapement wheel (12) for the other. The invention also relates to a clock movement comprising such a natural escapement.

Description

Technical field of the invention

The present invention relates to a natural escapement for clockwork also known by its name tangential impulse escapement. The present invention also relates to a timepiece movement comprising such an escapement.

Technology background

[0002] The principle of the natural escapement was imagined by Abraham Louis Breguet at the beginning of the 19th century. Breguet's natural escapement has the particular advantage of being a free escapement insofar as the balance is only disturbed by the operation of the escapement over a small fraction of its oscillation. Breguet's natural escapement also has the advantage of giving each alternation a direct and tangential impulse to the balance wheel. In other words, the energy is transferred directly from the escape wheel to the balance wheel, without passing through an anchor. Furthermore, the transmission of energy takes place only tangentially, so that the friction generated by the operation of this escapement is limited. Contrary to the balance wheel of a detent escapement, the balance wheel of a natural escapement does not present any lost shots; it receives a similar impulse at each alternation, in a symmetrical and more uniform way, so that the losses of mechanical energy by lost blow are suppressed. All these qualities thus make the natural exhaust one of the potentially most efficient exhausts.

[0003] Breguet nevertheless subsequently discovered that the natural escapement he had imagined had certain drawbacks, first and foremost of which we can cite the fact that the last escape wheel is not under the tension of the gear train when the first wheel gives the impetus or when the latter is at rest. The different sets of gears and the manufacturing quality of the various components that go into the composition of a natural Breguet escapement can thus cause incorrect positioning of the last escapement wheel and, consequently, poor functioning of the escapement s 'accompanied by extraneous noises. Furthermore, since the escape wheel is free, its position is unstable, so that the safety of operation of such a natural escapement is poor.

[0004] Of course, many improvements have been made to the original Breguet natural escapement in an attempt to overcome the drawbacks mentioned above. Nevertheless, despite the efforts of successive watch manufacturers, difficulties persist. Some watchmakers have thus proposed superimposing the two escapement wheels, a solution which, of course, increases the thickness of the movement and makes it difficult to integrate such a movement into a watch case. Other watch manufacturers have proposed positioning the lever between the two escapement wheels, in the plane of the latter. Again, such a solution is cumbersome, this time in the plane of movement. In addition, whether the escapement wheels are superimposed or whether the anchor is placed between the two escapement wheels, it has been realized in use that watchmakers experience difficulties in accessing the various components of the escapement, in particular when it came to adjusting the depth of penetration of the teeth of the first and second escapement wheel with the exit and entry pallets of the anchor.

Summary of the invention

The object of the present invention is to remedy the problems mentioned above as well as still others by providing a natural escapement for a watch movement which is in particular less bulky and whose anchor is more easily accessible. for measurement and adjustment.

[0006] To this end, the present invention relates to a natural escapement for a clock movement performing a succession of operating cycles each consisting of a first and a second alternation of a balance wheel which comprises a balance wheel as well as a balance plate fitted on an axis of the balance wheel, this natural escapement comprising a first escapement wheel arranged to be driven by a second wheel set, this first escapement wheel in turn driving a second escapement wheel escapement arranged in the same plane as the first escapement wheel, an anchor capable of pivoting around an anchor rod, this anchor comprising means for temporarily blocking the first escapement wheel during the first alternation, and means for temporarily blocking the second escape wheel during the second alternation, the anchor stem being situated outside an angle less than 180° and delimited by two straight lines which do not feels by the axis of the balance wheel and by a pivot axis of the first escapement wheel for one, and by the axis of the balance wheel and by a pivot axis of the second escapement wheel exhaust for the other.

According to special embodiments of the invention: the anchor comprises a first stop pallet for temporarily blocking the first escape wheel during the first alternation, and a second stop pallet for temporarily blocking the second escape wheel during the second alternation; the balance plate carries a balance pin by which this balance plate causes the anchor to pivot at each of the first and second alternations, the balance plate also carrying a second impulse pallet by which this balance plate receives a direct and tangential driving impulse of the second escapement wheel during the first alternation, and a first impulse pallet by which this balance wheel receives a direct and tangential driving impulse from the first escapement wheel during the second alternation , the balance pin being located outside an acute angle delimited by two straight lines which pass through the axis of the balance wheel and through the first impulse pallet for one, and through the axis of the balance wheel and by the second impulse pallet for the other; the first escape wheel comprises a toothing which extends in a single plane and by which this first escape wheel meshes with the second escape wheel and supplies the direct and tangential driving impulse to the balance plate during the second alternation; the second escape wheel comprises a toothing which extends in a single plane and by which this second escape wheel meshes with the first escape wheel and supplies the direct and tangential driving impulse to the balance plate during the first alternation; the anchor comprises a fork formed of a first and a second horn, the balance plate abutting by its balance pin against the first horn of the fork and causing the pivoting of this anchor in a first direction during the first alternation, and against the second horn during the second alternation, causing the lever to pivot in a second direction opposite to the first; the fork carries a pin which cooperates with the balance plate to prevent accidental movements of the fork; the first and second escape wheels are each one-piece and each comprise a single level of teeth.

The invention also relates to a clock movement comprising a natural escapement of the type described above.

[0009] Thanks to these characteristics, the present invention provides a natural escapement in which the anchor which alternately blocks and releases the first escapement wheel and the second escapement wheel has its anchor rod located outside an angle less than 180° and bounded by two straight lines which pass through the axis of the balance wheel and through a pivot axis of the first escapement wheel for one, and through the axis of the balance wheel and through a pivot axis of the second escape wheel for the other. This solution, which is much less bulky and therefore easier to house in a watch movement than when the lever is placed between the two escape wheels, also offers easier access to watchmakers and allows them to measure and more conveniently adjust the depth of penetration of the teeth of the first and second escapement wheels with the first and second anchor stop pallets, as well as the heights of the escapement wheels opposite the impulse pallets of the pendulum. Furthermore, the first and second escape wheels are each one-piece and each comprise a single level of teeth. In other words, these first and second escape wheels are not active according to two distinct stepped levels. They are therefore less bulky and easier to machine. In addition, the necessary indexing of the teeth serving to transmit the driving impulses to the balance plate when two superposed escape wheels are used is avoided. Indeed, in the case of the invention, the indexing of the single toothing of the first and second escapement wheels which ensures both the meshing of these two drive wheels with each other and the transmission of the driving impulses to the balance plate stems from the very shape of this toothing.

Brief description of figures

Other characteristics and advantages of the present invention will emerge more clearly from the following detailed description of an embodiment of a natural exhaust according to the invention, this example being given for purely illustrative and non-limiting purposes only. in conjunction with the attached drawing on which: FIG. 1 is an overall view of the natural exhaust according to the invention; FIG. 2A is a view of the natural escapement in its first extreme position at the start of a cycle; FIG. 2B is a view of the natural escapement in its rest position during the first alternation when the balance plate is about to cause the anchor to pivot; FIG. 2C is a view of the natural escapement at the moment when the first escapement wheel is released from its grip with the first stopper pallet, which allows the second mobile to drive, via the first escapement wheel escapement, the second escapement wheel, this second escapement wheel also giving, via its impulse tooth, a so-called direct and tangential driving impulse to the second impulse pallet of the balance plate; FIG. 2D is a view of the natural escapement at the moment when the pivoting of the second escapement wheel is again interrupted when, under the effect of the pivoting of the anchor, this second escapement wheel finds itself resting on the second stop pallet; FIG. 2E is a view of the natural escapement when the balance plate is in its second extreme position in which it is completely moved away from its rest position, which marks the end of the first alternation of operation of the natural escape; FIG. 2F is a view of the natural escapement at the moment when, during the second alternation, the balance plate has returned to its rest position and is about to cause the anchor to pivot again; FIG. 2G is a view of the natural escapement at the moment when the second escapement wheel is released from its grip with the second stopper pallet, which allows the second mobile to drive, via the first escapement wheel escapement, this second escapement wheel, the first escapement wheel giving a so-called direct and tangential drive impulse to the balance plate via the first impulse pallet; FIG. 2H is a view of the natural escapement at the moment when the pivoting of the first escapement wheel is again interrupted when, under the effect of the pivoting of the anchor, this first escapement wheel finds itself resting on the first stop pallet; FIG. 2I is a view of the natural escapement returning to its first extreme position, which marks the end of the operating cycle of the natural escapement according to the invention.

Detailed description of the invention

The present invention proceeds from the general inventive idea which consists in arranging the anchor of a natural escapement also known by its name tangential impulse escapement, so that its anchor rod is located outside an angle less than 180° and bounded by two straight lines which pass through the axis of the balance wheel and through a pivot axis of the first escapement wheel for one, and through the axis of the balance wheel and through a pivot axis of the second escape wheel for the other. Such an arrangement, much less cumbersome than when the anchor of the natural escapement is placed between the escapement wheels, also offers the watchmaker easier access to the first and second pallets for stopping the anchor and therefore greater convenience in measuring and adjusting the depth of penetration of these pallets into the teeth of the first and second escape wheels. This arrangement also makes it possible to better see the escape wheels when they communicate the driving impulse to the impulse pallets of the balance plate and therefore to more easily adjust the height of these escape wheels. Likewise, since the first and second escape wheels are only active along a single level, they are thinner and therefore less bulky and easier to machine. Furthermore, the indexing of their impulse teeth stems from the actual shape of their teeth and not from a tedious assembly of two superimposed escape wheels.

Designated as a whole by the general reference numeral 1, the natural escapement according to the invention is arranged to be driven by a second mobile 2 which meshes with a pinion 4 mounted fixed on an axis 6 of a first wheel escapement wheel 8. This first escapement wheel 8 in turn meshes via a toothing 10 with a second escapement wheel 12 which pivots around an axis 14.

[0013] The natural escapement 1 also comprises a balance wheel 16 which comprises a balance wheel 18 on an axis 20 of which is fitted a balance plate 22. This balance plate 22 carries a balance pin 24 as well as a first and a second pulse pallet 26 and 28 whose respective roles will be described below.

The natural escapement 1 according to the invention finally comprises an anchor 30 pivoted around an anchor rod 32 and which carries a first stop pallet 34 and a second stop pallet 36. These first and second stop pallets 34 and 36 can be made in one piece with the anchor 30 or else be attached to this anchor 30 in the form of two separate parts. Thanks to these first and second stop pallets 34 and 36 which penetrate respectively into the toothing 10 of the first escapement wheel 8 and into a toothing 38 of the second escapement wheel 12, the lever 30 is able to alternately locking and releasing these first and second escape wheels 8 and 12. The anchor 30 also comprises a fork 40 formed of a first and a second horn 42a and 42b and which carries a dart 44. This dart 44 cooperates with the balance plate 22 and has the function of preventing accidental movements of the fork 40 outside the periods during which the balance plate 22 is in its rest position.

[0015] According to the invention, the pivot point of the anchor 30, materialized by the anchor rod 32, is outside the angle α of less than 180° and delimited by two straight lines which pass through the axis 20 of the balance wheel 18 and by the axis 6 of the first escapement wheel 8 for one, and by the axis 20 of the balance wheel 18 and by the axis 14 of the second wheel of exhaust 12 for the other. The natural escapement 1 according to the invention is therefore less bulky than the natural escapements of the prior art in which the anchor is usually placed between and above the first and second escapement wheels. The natural escapement 1 according to the invention is therefore simpler to house in the clock movement whose operation it regulates. Similarly, the arrangement of the anchor 30 outside the angle α of less than 180° makes the interventions of the watchmaker less difficult, in particular as regards the measurement and adjustment of the depth of penetration of the first and second stop pallets 34 and 36 in the toothings 10 and 38 of the first and second escape wheel 8 and 12, and measurements and adjustments of the heights of the first and second wheels 8 and 12 with respect to the first and second pallets pulse 26 and 28 of the balance plate 22. The natural escapement 1 is completed by a first and a second stop 46a and 46b which limit the movement of the anchor 30 in pivoting.

In the mode of execution of the natural escapement 1 according to the invention illustrated in the drawing, it is assumed that the second mobile 2 which supplies the natural escapement 1 with the energy necessary for its operation rotates in the direction clock hands. The second mobile 2 therefore tends to rotate the pinion 4 and the first escapement wheel 8 on the axis 6 of which the pinion 4 is fixed in the counterclockwise direction, and the second escapement wheel 12 in the counterclockwise direction. hourly.

[0017] An operating cycle of the natural escapement 1 according to the invention comprises two alternations during which the balance plate 22 will go successively from a first extreme position to a second extreme position passing through a median rest position , then from its second extreme position to its first extreme position by going back a second time through its middle rest position. Thus, at the start of a cycle (see FIG. 2A), the first escapement wheel 8 bears against the first stop pallet 34 and the natural escapement 1 is blocked by pressing the anchor 30 against the second stop 46b. Indeed, the pulling angle formed by pressing the tip of the tooth of the first escapement wheel 8 on the first stop plate 34 opposes a resistance to the release of the anchor 30 by tending to cause this anchor to pivot. 30 counterclockwise against the second stop 46b. This function of pulling the anchor 30 onto the second stop 46b by the first escapement wheel 8 during the free part of the alternation of the balance plate 22 is similar to that of Swiss lever escapements. The balance plate 22 then leaves this first extreme position by rotating counterclockwise. At a given moment of its movement during the first alternation (see FIG. 2B), the balance plate 22 arrives in its middle rest position. Just before reaching this position, the balance plate 22 abuts by its balance pin 24 against the first horn 42a of the fork 40 and causes the lever 30 to pivot clockwise. The clockwise pivoting of the anchor 30 has the effect of releasing the first escapement wheel 8 from its grip with the first stop plate 34, which allows the second wheel set 2 to drive, via the first escape wheel 8, the second escape wheel 12 clockwise (see Figure 2C). The pivoting of the second escapement wheel 12 is again interrupted when, under the effect of the pivoting of the anchor 30, this second escapement wheel 12 finds itself resting on the second stop pallet 36, this position being retained thanks to the support of the anchor 30 against the first stop 46a (see FIG. 2D). Indeed, the pulling angle formed by pressing the tip of the tooth of the second escapement wheel 12 on the second stop plate 36 opposes a resistance to the release of the anchor 30 by tending to cause this anchor to pivot. 30 clockwise against the first stop 46a. This function of pulling the lever 30 onto the first stop 46a by the second escapement wheel 12 during the free part of the alternation of the balance plate 22 is similar to that of Swiss lever escapements.

It will be noted that at the same time as the first escapement wheel 8 drives the second escapement wheel 12 in clockwise pivoting, the second escapement wheel 12 also gives a driving impulse to the balance plate 22 via one of its teeth 48 called the impulse tooth which drives the second impulse pallet 28 (see FIG. 2C). This driving impulse is called direct and tangential impulse because it is given directly by the second escapement wheel 12 to the balance plate 22 and the path of the impulse tooth 48 catches up with that of the second impulse pallet 28 of the plate. of pendulum 22 tangentially, which allows an almost punctual contact and without friction. The balance plate 22 thus moves to its second extreme position in which it is completely moved away from its rest position, which marks the end of the first alternation of operation of the natural escapement 1 (see FIG. 2E).

[0019] At the start of the second alternation of operation of the natural escapement 1, the balance plate 22, recalled by the spiral spring of the balance (not visible in the drawing), begins to rotate clockwise until that it comes to abut by its balance pin 24 against the second horn 42b of the fork 40 and causes the pivoting of the lever 30 in the counterclockwise direction (see FIG. 2F). The anti-clockwise pivoting of the anchor 30 has the effect of releasing the second escape wheel 12 from its grip with the second stop plate 36, which allows the second wheel set 2 to drive, via the first escape wheel 8, the second escape wheel 12 clockwise (see Figure 2G). The pivoting of the second escapement wheel 12 is again interrupted when, under the effect of the pivoting of the lever 30, the first escapement wheel 8 finds itself resting on the first stop pallet 34, this position being kept thanks to the support of the anchor 30 against the second stop 46b (see FIG. 2H). Indeed, the pulling angle formed by pressing the tip of the tooth of the first escapement wheel 8 on the first stop plate 34 opposes a resistance to the release of the anchor 30 by tending to cause this anchor to pivot. 30 counterclockwise against the second stop 46b.

It will be noted that at the same time as the first escapement wheel 8 drives the second escapement wheel 12 in clockwise pivoting, the first escapement wheel 8 also gives a so-called direct and tangential driving impulse to the balance plate 22 via one of its teeth 50 called the impulse tooth which drives the first impulse pallet 26 (see FIG. 2G). The impulse is so named because it is given directly by the first escapement wheel 8 to the balance plate 22 and the path of the impulse tooth 50 catches up with that of the first impulse pallet 26 of the balance plate 22 tangentially, which allows an almost punctual and frictionless contact. The balance plate 22 thus returns to its first extreme position, which marks the end of an operating cycle of the natural escapement 1 (see FIG. 21).

It goes without saying that the present invention is not limited to the embodiment which has just been described and that various modifications and simple variants can be envisaged by those skilled in the art without departing from the scope of the invention. as defined by the claims appended to this patent application. It will be noted in particular that the function of the first and second stops 46a and 46b can also be ensured by a specific shape of the first and second stop plates 34 and 36 and of the impulse teeth 48 and 50. It will also be noted that the pin balance wheel 24 is located outside an acute angle β delimited by two straight lines which pass through the axis 20 of the balance wheel 18 and through the first impulse pallet 26, respectively through the second impulse pallet 28.

Nomenclature

1. Natural escapement 2. Second mobile 4. Pinion 6. Axis 8. First escapement wheel 10. Toothing 12. Second escapement wheel 14. Axis 16. Balance wheel 18. Balance wheel 20. Axis 22 Balance plate 24. Balance pin 26. First impulse pallet 28. Second impulse pallet 30. Anchor 32. Anchor rod 34. First stop pallet 36. Second stop pallet 38. Toothing 40 Fork 42a, 42b. Horns 44. Dart 46a. First stop 46b. Second stop 48. Impulse tooth 50. Impulse tooth

Claims (9)

1. Natural escapement (1) for a clock movement carrying out a succession of operating cycles each consisting of a first and a second alternation of a balance wheel (16) which comprises a balance wheel (18) as well as a balance plate (22) fitted on an axis (20) of the balance wheel (18), this natural escapement (1) comprising a first escapement wheel (8) arranged to be driven by a second wheel set (2 ), this first escapement wheel (8) in turn driving a second escapement wheel (12) arranged in the same plane as the first escapement wheel (8), an anchor (30) capable of pivoting about an anchor rod (32), this anchor (30) comprising means for temporarily blocking the first escape wheel (8) during the first alternation, and means for temporarily blocking the second escape wheel ( 12) during the second alternation, the anchor rod (32) being located outside an angle (α) of less than 180° and delimited by two straight lines which pass through the axis (20) of the balance wheel (18) and through a pivot axis (6) of the first escapement wheel (8) for one, and through the axis (20) of the balance wheel (18) and by a pivot axis (14) of the second escapement wheel (12) for the other. 2. Natural escapement (1) according to claim 1, characterized in that the anchor (30) comprises a first stop pallet (34) to temporarily block the first escapement wheel (8) during the first alternation , and a second stop pallet (36) for temporarily blocking the second escapement wheel (12) during the second alternation. 3. Natural exhaust (1) according to one of claims 1 and 2, characterized in that the balance plate (22) carries a balance pin (24) by which this balance plate (22) causes the pivoting of the anchor (30) at each of the first and second alternations, the balance plate (22) also carrying a second impulse pallet (28) by which this balance plate (22) receives a direct and tangential driving impulse from the second escapement wheel (12) during the first alternation, and a first impulse pallet (26) through which this balance plate (22) receives a direct and tangential driving impulse from the first escapement wheel (8) during of the second alternation, the balance pin (24) being located outside an acute angle (β) delimited by two straight lines which pass through the axis (20) of the balance wheel (18) and through the first pallet d impulse (26) for one, and by the axis (20) of the balance wheel (18) and by the s second impulse paddle (28) for the other. 4. Natural escapement (1) according to claim 3, characterized in that the first escapement wheel (8) comprises a toothing (10) which extends in a single plane and by which this first escapement wheel (8 ) meshes with the second escapement wheel (12) and supplies the direct and tangential drive impulse to the balance plate (22) during the second alternation. 5. Natural escapement (1) according to claim 4, characterized in that the second escapement wheel (12) comprises a toothing (38) which extends in a single plane and by which this second escapement wheel (12 ) meshes with the first escapement wheel (8) and supplies the direct and tangential drive impulse to the balance plate (22) during the first alternation. 6. Natural exhaust (1) according to one of claims 1 to 5, characterized in that the anchor (30) comprises a fork (40) formed of a first and a second horn (42a, 42b), the balance plate (22) abutting by its balance pin (24) against the first horn (42a) of the fork (40) and causing the pivoting of this lever (30) in a first direction during the first alternation, and against the second horn (42b) during the second alternation, causing the anchor (30) to pivot in a second direction opposite to the first. 7. Natural exhaust (1) according to claim 6, characterized in that the fork (40) carries a pin (44) which cooperates with the rocker plate (22) to prevent accidental movement of the fork (40). 8. Natural exhaust (1) according to one of claims 1 to 7, characterized in that the first and second escapement wheels (8, 12) are each one-piece and each comprise a single level of teeth. 9. Clock movement comprising a natural escapement (1) according to one of claims 1 to 8.