CH714200B1 - An escapement device for a mechanical watch movement comprising an escapement with two escapement moving parts. - Google Patents

Abstract

The invention relates to an escapement device for a mechanical watch movement, comprising a first escapement mobile (3), a second escape mobile (4) directly meshed with the first escape mobile (3), an anchor (2) provided with an anchor rod (2c) and a fork (2e) arranged to cooperate with a pin (1a) of the balance plate (1), and two pallets (2a, 2b) mounted directly on the anchor rod (2c), each pallet comprising an impulse plane (2a1).

Description

Technical area

The present invention relates to a mechanical watch movement, in particular a mechanical watch movement comprising an escapement with two synchronized escapement wheels.

State of the art

The purpose of the escapement of timepieces is to transmit to the balance the energy it needs to oscillate, and to block the finishing gear at least once for each oscillation of the balance, in order to adjust the rate. of the watch according to the periods of the balance.

[0003] For this purpose, the Swiss lever escapement is widely used. It comprises an escape wheel and an anchor, a first end of which is provided with paddles and a second end of which is provided with a fork. At each alternation, a tooth of the escape wheel transmits an impulse to the anchor which rocks. The fork then comes into contact with the plate pin on the balance shaft, to set the latter in rotation. The escape wheel is blocked by the other pallet. The plateau pin then works with the fork to release the anchor and start a new alternation. This type of exhaust has the advantage of starting on its own and being robust to shocks, but its efficiency is limited, in particular due to a short pulse phase.

[0004] Many exhausts are also known comprising two escape wheels. By way of example, the natural Breguet escapement as well as the escapement described in EP2487546 make it possible to improve efficiency by giving an impulse directly to the balance at each alternation. The construction of this escapement is complex and involves in particular impulse paddles (called “mustaches”) on the balance plate, and additional stop paddles on the anchor. Making the tray with these pallets is difficult, because it involves at least three levels. In addition, the assembly is delicate.

[0005] CH701921 describes another escapement in which the anchor is in two parts sliding one relative to the other. It carries two paddles mounted on the rod of the anchor and each collaborating with one of the two escape wheels. The two escape wheels are meshed with each other through a return or differential. The manufacture of this anchor in two parts is complex; the intermediate gear between the two escape wheels makes the mechanism complex.

Brief summary of the invention

[0006] An object of the present invention is to provide an escapement device for a mechanical watch free from the above limitations.

[0007] In particular, an object of the invention is to improve the efficiency of the escapement compared with the Swiss lever escapement.

[0008] These goals are achieved in particular by means of an exhaust device comprising: a first exhaust mobile; a second exhaust mobile meshed with the first exhaust mobile; an anchor provided with a fork designed to cooperate with a balance plate pin, and with an anchor rod; two paddles mounted directly on the anchor rod, each paddle comprising an impulse plane (2a1).

[0009] The invention also relates to a mechanical watch movement comprising such an escapement device, as well as a balance plate on a balance shaft, the balance plate carrying a plate pin; the impulses being transmitted alternately by one of the escape wheels to the balance plate, through the impulse plane of one of the pallets of the anchor.

Each pallet advantageously further comprises a rest plane forming a bearing surface for blocking one of the exhaust wheels during a rest phase.

The movement employs a relatively easy to manufacture balance plate, identical or similar to the plate of a Swiss lever escapement.

[0012] The impulse is transmitted indirectly through the paddles and the rod of the anchor. The escapement wheels in turn push back the anchor, which gives an impetus to the balance via the pin on the balance plate.

[0013] The impulse is transmitted via the impulse surface of the pallets on the rod of the anchor.

This movement allows high efficiency thanks to an optimized pulse phase.

[0015] The pallets are arranged on the rod substantially at the level of the center distance of the two mobile exhaust. This makes it possible to maximize the pulse length (therefore the energy transmitted per pulse), while improving the direction of the force transmitted, and therefore the torque of the pulse. "Substantially" means here that the line which joins the axis of the two escapement wheels, passing through the center of the impulse surface of the two vanes, preferably forms a rectilinear line, or a succession of rectilinear segments with obtuse angles greater than 135 °, preferably greater than 160 °, between successive segments.

[0016] The exhaust preferably comprises exactly two said pallets.

The pallets are mounted on the rod of the anchor so that the impulse plane (typically the longest side of the pallet) forms an angle less than 45 ° with the longitudinal axis of the rod of the anchor. Palettes can also be merged into a single component, or even merged with the anchor stick.

[0018] The length of the pulse plane is thus optimized.

[0019] The mobile exhaust can be constituted by escape wheels.

[0020] In one embodiment, each exhaust mobile comprises two superimposed wheels, one toothed, making it possible to engage the two exhaust wheels, and the other having teeth cooperating with the vanes.

In another embodiment, the escape wheels are provided with cleats integral with the toothed wheel meshing of the two wheels cooperating with said pallets to give impulses to the anchor during a pulse phase , and to block the rotation of the escape wheels during a rest phase.

The use of cleats mounted on the rim of the toothed wheel of the exhaust mobile reduces the inertia of the exhaust mobile, compared to a solution using two superimposed wheels.

Brief description of the figures

[0023] Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which: FIG. 1 illustrates an example of an escapement and of a balance plate during the rest phase. • Figure 2 illustrates an example of an exhaust and a balance plate during the release phase. • Figure 3 illustrates an example of an escapement and a balance plate during the impulse phase. • FIG. 4 illustrates an example of an escapement and a balance plate during the rest phase of the following alternation.

Example (s) of embodiment of the invention

[0024] For reasons of simplification of the figures and of the description, only the escapement and the balance plate will be illustrated and described. The other components of the watch movement can be conventional.

FIG. 1 illustrates these components during the rest phase of a first alternation. The escapement comprises two escapement wheels 3 and 4, at least one of which is integral with the last pinion of the movement finishing train. Each exhaust mobile 3, 4 comprises a series of peripheral teeth 3b in a first plane. They are thus meshed by these teeth directly to one another.

[0026] The shape of the teeth 3b is intended to allow high efficiency meshing. These teeth do not collaborate with the pallets of the anchor, and therefore do not include an impulse plane.

The direct gear between the two mobile exhaust 3 and 4, without intermediate return, simplifies the mechanism and reduces the play between the two mobile. In the example illustrated, the mobile 3 turns clockwise while the mobile 4 turns counterclockwise.

The two mobile exhaust 3, 4 further include cleats (or teeth) 3a, 4a respectively which play the role of teeth of a conventional escape wheel. These extend from the internal face of the serge, and rise in a plane distinct from the main plane of the mobile. The cleats 3a on the first escapement mobile 3 are out of phase with respect to the cleats 4a on the second exhaust mobile 4 so that they act alternately with the vanes 2a, 2b of the anchor.

Each cleat 3a, 4a comprises an attachment portion 3a3 to connect it individually to the internal face of the rim (or rim) 3c of the associated exhaust mobile. At least part of the cleats can also be mounted on an arm (radius) 3d of this exhaust mobile.

The small side 3a1 of each cleat, at the distal end opposite to the attachment with the rim 3c, forms a rest plane to rest against the pallets. The face 3a2 of the cleats facing the outside of the exhaust mobile is longer and forms an impulse surface.

This arrangement makes it possible to share the impulse between the exhaust mobile and the pallet on the anchor, as will be seen. Other forms of cleats are conceivable, including cleats adapted for a thrust plane totally on the anchor or totally on the cleat.

An anchor 2 makes it possible to alternately block an escapement mobile then the other during the successive rest phases, and to transmit the energy to a balance plate 1 during the impulse phases. The anchor 2 rotates around a 2D axis and has a rod of the anchor 2c (or rod) between this axis and a fork of the anchor 2e at the end opposite the axis. The fork and stinger are conventional and similar to that of a Swiss lever escapement.

The rod of the anchor 2c comprises an intermediate portion with two side faces which may be non-parallel to each other. In one embodiment, the angle between these faces is between 0 ° and 45 °, preferably between 15 and 30 °. One of the two pallets 2a and 2b is mounted on each of these faces.

Pins can be provided on each side of the anchor rod to limit its angular movements.

Two pallets 2a, 2b, for example ruby pallets, are mounted on the rod of the anchor, one on each side. The pallet 2a is intended to meet the cleats 3a of the exhaust mobile 3 while the other pallet 2b is intended to meet the tabs 4a of the second exhaust mobile.

The pallets 2a, 2b have a substantially trapezoidal shape with a long pulse plane 2a1 opposite the rod of the anchor, and a shorter rest plane 2a2 on the side of the fork of the anchor 2a. Their shape can be identical to that of a Swiss lever escapement pallet, by reversing the position of the rest and impulse surfaces. This arrangement results in impulse planes of the two pallets which are not parallel to each other, and which are provided on one of the two long sides of the pallet. The rod of the anchor 2c is advantageously notched and therefore provided with at least one opening to reduce its inertia.

The balance plate 1 can be identical to the plate conventionally used on Swiss lever escapements, and for example consist of two discs interconnected by a barrel and mounted on the balance axis 1b which also carries the balance (not illustrated).

The upper disc 1c (large plate) carries a plate peg 1a which collaborates with the fork of the anchor 2e. The ankle section is “half-moon”, or more exactly circular with a part of the circle which is removed to allow the ankle to enter the inside of the fork with sufficient margin.

The lower disc 1d (small plate) has a notch 1d1 at its periphery, which allows the stinger of the anchor to pass.

The escapement is illustrated in the rest phase in Figure 1. In this phase, the pallet 2a on the anchor 2 maintains the cleat 3a of the exhaust mobile 3 on its rest plane to prevent it from rotating . The rest plane 2a2 of the pallet 2a rests directly on the rest plane 3a1 of the cleat 3a which then acts as a chock and blocks the exhaust mobile. The exhaust mobile 4 is meshed with the exhaust mobile 3 and therefore also prevented from rotating. In this phase, the plate 1, integral with the balance axis 1b, travels an additional arc thanks to its kinetic energy and to the energy accumulated in the hairspring (not shown).

The same exhaust is illustrated in the release phase in Figure 2. During this phase, the plate peg 1a comes into contact with the fork 2e of the anchor 2 which then rotates clockwise, so as to release the pallet 2a of the cleat 3a. The mobile escape 3 operates a very slight decline. At the end of the clearance, the pallet and the corresponding cleat rest point to point.

[0042] FIG. 3 illustrates the exhaust in the pulse phase. The cleat 3a is no longer retained by the rest plane of the pallet 2a, the exhaust mobile 3 starts to rotate thanks to the finishing gear. It then transmits an impulse to the anchor 2 via the impulse plane 2a1 of the pallet 2a and via the impulse plane 3a2 of its cleat 3a. The pulse length is equal to the length of the pulse plane 2a1 of the vane plus the length of the pulse plane 3a2 of the cleat.

The anchor 2 continues to tilt and then impels the balance via the plate pin 1a and the fork 2e on the balance plate 1.

Figure 4 illustrates the exhaust to the next rest phase. The second exhaust mobile 4, meshed by the mobile 3 and by the finishing gear, makes an additional angle until the cleat 4a comes into contact with the rest plane of the pallet 2b on the anchor 2. The plate pin 1a is released from the fork 2e of the anchor 2, and the balance traverses its additional arc, before changing the direction of rotation.

Reference numbers used in figures

1 Balance plate 1a Plate pin 1b Balance pin 2 Anchor 2a First pallet 2a1 Impulse plane of the first pallet 2a2 Rest plane of the first pallet 2b Second pallet 2c Rod of the anchor 2D Axis of the 'anchor 2 <e> Fork of the anchor 3 First escape mobile 3a Cleat of the first escape mobile 3a1 Rest plane of the cleats 3a2 Impulse plane of the cleats 3a3 Attachment portion 3b Peripheral teeth 3c Serge of the mobile exhaust 3 3d Arm of the exhaust mobile 3 4 Second exhaust mobile

Claims (10)

1. Escape device for a mechanical watch movement, comprising: a first exhaust mobile (3); a second exhaust mobile (4) directly meshed with the first exhaust mobile (3); an anchor (2) fitted with an anchor rod (2c), the anchor (2) being provided with a fork (2e) arranged to cooperate with a balance plate pin (1); two pallets (2a, 2b) mounted directly on the rod of the anchor, each pallet comprising an impulse plane (2a1). 2. Exhaust device according to claim 1, each pallet (2a, 2b) further comprising a rest plane (2a2) forming a bearing surface for blocking one of the exhaust wheels during a rest phase. 3. Exhaust device according to one of claims 1 and 2, wherein the vanes (2a, 3a) are arranged on the rod substantially at the level of the center distance of the two exhaust wheels. 4. Exhaust device according to one of claims 2 and 3, wherein each said mobile exhaust (3, 4) comprises cleats (3a and 4a) cooperating with the pulse plane of the vanes (2a, 2b ) to give impulses to the anchor (2) during an impulse phase, and with the rest plane (2a2) of the vanes (2a, 2b) to block the rotation of the escape wheels (3, 4 ) during the rest phase. 5. Exhaust device according to claim 4, wherein each exhaust mobile comprises a lower face defining a first plane and an upper face defining a second plane, each said cleat extending transversely to said planes, and comprising a rest plane (3a1) and an impulse plane (3a2) outside the space between the first and the second plane. 6. Exhaust device according to claim 5, wherein the distal end of each cleat (3a, 4a) forms said rest plane (3a1) intended to bear against the vanes (2a, 2b). 7. Exhaust device according to one of claims 4 and 5, wherein the face (3a2) of the tabs (3) facing the outside of the exhaust wheels (3, 4) forms an impulse surface. 8. Exhaust device according to claim 6, wherein the rest plane (3a1) of the cleat (3) is shorter than its impulse plane (3a2). 9. Mechanical watch movement comprising: a balance plate (1) on a balance shaft (1b), the balance plate carrying a plate pin (1a); an exhaust device according to one of the preceding claims; arranged so that the impulses are transmitted alternately by one of the escape wheels to the balance plate, through the impulse plane (2a1) of one of the vanes and of the rod of the anchor. 10. Wristwatch comprising a watch movement according to claim 9.