Abstract
The invention relates to an escapement device for a mechanical timepiece comprising an escapement wheel cooperating with a rocker and a mobile element, the rocker cooperates with the escapement wheel by blocking means and with the balance plate by release means, the mobile element comprises elastic means and cooperates with the teeth of the escapement wheel by winding means and with the balance wheel plate by impulse means, this space-saving escapement device is able to supply the balance wheel with an almost constant quantity of energy within a variable barrel torque range.
Claims
1. An escapement device for a mechanical timepiece including: an escapement wheel comprising teeth, a rocker, a mobile element, at least one piece forming part of an oscillator of the timepiece, such as a balance plate, the escapement wheel cooperating with the rocker and the mobile element, the rocker cooperating with the escapement wheel by blocking means and with the piece forming part of the oscillator by release means, the mobile element comprising elastic means arranged to store elastic energy, and cooperating with the escapement wheel by winding means and with the piece forming part of the oscillator by impulse means, characterized in that: the winding means are arranged to carry out a phase of winding the elastic means along a first direction of rotation of the balance and the impulse means are arranged to carry out an impulse phase given by the mobile element to the piece forming part of the oscillator during the rotation of the balance along at least a second direction of rotation of the balance, and in that: the impulse is given directly from the mobile element to the piece forming part of the oscillator.
2. The escapement device according to claim 1 characterized in that a first blocking position of the rocker after the phase of winding the elastic means is different from a second blocking position of the rocker after the impulse phase given by the mobile element to the piece forming part of the oscillator.
3. The escapement device according to claim 1 characterized in that the mobile element is blocked by a tooth of the escapement wheel after the phase of winding the elastic means.
4. The escapement device according to claim 1, characterized in that the impulse means comprise: at least one finger or lever protruding from the piece forming part of the oscillator, and/or at least one impulse arm protruding from the mobile element.
5. The escapement device according to claim 1, characterized in that the winding means comprise: at least one tooth of the escapement wheel, and/or at least one winding arm of the mobile element.
6. The escapement device according to claim 1, characterized in that the piece forming part of the oscillator comprises two fingers or levers forming a double lift able to receive energy coming from of the mobile element in both directions of rotation of the balance.
7. The escapement device according to claim 1, characterized in that the elastic means of the mobile element are formed by a spiral type spring.
8. The escapement device according to claim 1, characterized in that the elastic means of the mobile element are formed by a leaf spring.
9. The escapement device according to claim 1, characterized in that the elastic means of the mobile element are formed by leaf springs, so as to form a flexible guiding system without any physical axis of rotation.
10. The escapement device according to claim 1, characterized in that the piece forming part of the oscillator is a balance plate.
11. A timepiece provided with an escapement device according to claim 1.
Description
[0062] The characteristics and advantages of the invention will emerge from the following description, with reference to the appended drawings in which:
[0063] FIG. 1 represents a form of execution of the escapement device according to the invention,
[0064] FIG. 2a represents the first blocking position of the escapement device of FIG. 1,
[0065] FIG. 2b represents the situation of the escapement device of FIG. 1 after the disengagement when the balance rotates in a first direction of rotation, particularly the counterclockwise direction,
[0066] FIG. 2c represents the second blocking position of the escapement device of FIG. 1 while the balance rotates in the first direction of rotation,
[0067] FIG. 3a represents the second blocking position of the escapement device of FIG. 1 while the balance rotates in a second direction of rotation, particularly the clockwise direction,
[0068] FIG. 3b represents the situation of the escapement device of FIG. 1 after the disengagement when the balance rotates in the second direction of rotation,
[0069] FIG. 3c represents the position of the different mobile elements of the escapement device of FIG. 1 after the impulse given by the mobile element 3 to the balance plate,
[0070] FIG. 4a represents the balance plate of the escapement of FIG. 1,
[0071] FIG. 4b represents an alternative execution of the balance plate of the escapement of FIG. 1,
[0072] FIG. 4c represents the phase of winding of the spring 3.4 with the alternative execution of the balance plate of FIG. 4b,
[0073] FIG. 5 represents a second alternative execution of the escapement according to the invention,
[0074] FIG. 6 represents a third alternative execution of the escapement according to the invention.
[0075] A form of execution of the escapement device according to the invention is represented in FIG. 1. The escapement device according to FIG. 1 comprises: [0076] an escapement wheel 1 comprising teeth 1.2 forming part of the winding means, driven by the barrel through transmission or finishing wheels not represented; this escapement wheel 1 rotates around an axis 1.1 in the counterclockwise direction. [0077] a rocker 2 pivoting around an axis 2.1, including blocking means and release means. The movement of this rocker is limited by limitation stops B1 and B2, [0078] a mobile element 3 pivoting around an axis 3.1, including a spring 3.4 mounted between a static part of the timepiece and the mobile element 3, a first impulse arm 3.2 forming part of impulse means and a second winding arm 3.3 forming part of the winding means mentioned above. The movement of this mobile element 3 is limited by a limitation stop B3.
[0079] In the represented example, the rocker 2 can have the general shape of an asymmetrical anchor equipped with a rod ending with a fork 2.4. The blocking means can correspond to the two arms 2.2 and 2.3 of the anchor or form part of the two arms of the anchor (attached pallets can also be provided), while the release means can correspond to the fork 2.4 or particularly to horns of the fork 2.4.
[0080] In the present application, with regard to the balance plate 4, it is considered to be comprised in the escapement system, although in some documents does not directly form part of the escapement device. Consequently, the balance plate 4 is also represented in FIG. 1. This balance plate 4 pivots around an axis 4.1 and comprises release means (here in the form of a finger or a lever 4.2) and energy receiving means 4.3, these energy receiving means 4.3 forming part of the impulse means mentioned above. In the example represented, the release means can be a finger or a lever 4.2, a finger or a lever protruding from the periphery of the balance plate 4 and the energy receiving means 4.3 forming part of the impulse means can form another finger or another lever protruding from the periphery of the balance plate 4. As a side note, this roller 4 also forms part of an oscillator device of the timepiece, particularly of a sprung-balance assembly of the timepiece.
[0081] The following figures describe the main operating steps of the escapement device according to the invention.
[0082] FIGS. 2a to 2c represent the different steps of the phase of winding or providing elastic potential energy to the spring 3.4 of the mobile element 3 by the escapement wheel.
[0083] FIG. 2a represents a first blocking position of the escapement device of FIG. 1. In this position, a tooth of the escapement wheel rests on the blocking means (the arm 2.3 of the rocker 2) and the movement of the rocker is limited by the stop B1. The impulse arm 3.2 of the mobile element 3 rests on the stop B3 under the effect of the return torque of the spring 3.4. The balance 4, which rotates in a first direction of rotation, in this case the counterclockwise direction in FIG. 2a, is in the position just before the disengagement.
[0084] FIG. 2b represents the situation after the disengagement. Under the effect of the torque of the escapement wheel 1, the mobile element 3 rotates in the clockwise direction and provides elastic potential energy to the spring 3.4. It is noted that in this example of execution, the arm 3.2 does not come into contact with the balance plate 4 during the winding of the spring 3.4.
[0085] FIG. 2c represents a second blocking position of the escapement device of FIG. 1. In this position, a tooth of the escapement wheel 1 rests on the blocking means (the arm 2.2 of the rocker 2) and the movement of the rocker is limited by the stop B2. The arm 3.3 of the mobile element 3 is blocked by another tooth of the escapement wheel 1. Between the two blocking positions, the mobile element 3 is moved by an angle , and the energy provided by the escapement wheel to the spring 3.4 is:
[00001]
k being the constant of the spring.
[0086] FIGS. 3a to 3c represent the different steps of the energy transmission phase from the spring 3.4 to the balance.
[0087] FIG. 3a represents (like FIG. 2c) the second blocking position of the escapement device of FIG. 1. However, unlike FIG. 2c, the balance plate 4 rotates in a second direction of rotation, in this case the clockwise direction, and is in the position just before the disengagement.
[0088] FIG. 3b represents the situation after the disengagement. The rocker 2 moves from the second blocking position to the first blocking position, thus releasing the escapement wheel 1 and the arm 3.3 of the mobile element 3. The arm 3.2 of the mobile element 3, under the effect of the torque of the spring 3.4, gives the impulse to the energy receiving means 4.3 of the balance plate 4, it is noted that this impulse is of the direct type, that is to say that the arm 3.2 directly transmits the torque to the balance plate 4 without passing through an intermediate element.
[0089] FIG. 3c represents the position of the different mobile elements of the escapement device after the impulse phase given by the mobile element 3 to the balance plate 4.
[0090] The balance therefore always receives the same amount of energy coming from the spring 3.4 to the nearest transmission efficiency, if the torque of the escapement wheel is greater than or equal to the torque of the spring 3.4. In other words, the impulse energy is transmitted directly by the spring 3.4, and not by the rocker 2 (the anchor).
[0091] It is observed that the desired aim has been achieved: the escapement device according to the invention makes it possible to provide the balance with a practically constant amount of energy in a variable torque range of the barrel. The device according to the invention requires few components compared to the devices known to the prior art, moreover its space requirement is very small, which makes it possible to easily integrate it into a small-volume timepiece.
[0092] FIGS. 4b and 4c represent alternative executions of the escapement according to the invention.
[0093] FIG. 4a represents the balance plate 4 of the escapement of FIG. 1, which is provided with release means (the finger or the lever 4.2) and energy receiving means (the finger or the lever 4.3), which as explained respectively take the form of a finger or a lever protruding from the periphery of the balance plate 4.
[0094] In FIGS. 4b and 4c, the energy receiving means of the balance plate 4 comprises two fingers or levers 4.3.1. and 4.3.2, thus forming a double lift. The disengaging receiving means for their part remain unchanged and take the form of a finger or a lever t 4.2, of a finger or a lever protruding from the periphery of the balance plate 4.
[0095] FIG. 2b shows that during the phase of winding the spring 3.4, the arm 3.2 does not come into contact with the balance plate 4. Given the low inertia of the mobile element 3, the movement of the escapement wheel 1 during the phase of winding the spring 3.4 can be faster than that of the rocker 2 which is meshed with the balance plate 4. This desynchronization can cause the instability of the escapement device when it is positioned in the second blocking position.
[0096] To synchronize the movement of the escapement wheel 1 with that of the rocker 2, the balance plate 4 represented in FIG. 4b can be advantageously used. In this alternative execution, the first finger or lever 4.3.1 comes into contact with the arm 3.2 of the mobile element 3 during the phase of winding the spring 3.4, namely during the rotation of the balance in a first direction of rotation. The second finger or lever 4.3.2 is used to receive energy from the spring after the disengagement when the balance rotates in a second direction of rotation.
[0097] FIG. 4c represents the escapement device according to the invention during the phase of winding the spring 3.4 with the new variant of the balance plate 4.
[0098] FIG. 5 represents a second alternative execution of the escapement according to the invention.
[0099] In this new execution, the spiral spring 3.4 is replaced by a leaf spring 3.5 engaged in a slot in the mobile element 3.
[0100] FIG. 6 represents a third alternative execution of the escapement according to the invention.
[0101] In this third alternative execution, the mobile element 3 pivoted on the axis 3.1 of the previous figures is replaced by a flexible guiding system 3a which does not have a physical axis of rotation. Indeed, the arms 3.2 and 3.3 of the mobile element 3 are connected to a static part of the timepiece by leaf springs which authorize the winding and impulsion phases described above.
[0102] It will be understood that various modifications and/or improvements obvious to those skilled in the art can be made to the different embodiments of the invention described in the present description without departing from the scope of the invention defined by the appended claims.
[0103] Particularly, the rocker can have any shape and is not limited to an anchor.
[0104] Finally, the mobile element can give the impulse to any part of the balance or even to another piece forming part of the oscillator, and not necessarily to a finger or a lever formed on the balance plate. For example, toothed sectors or portions can be provided.
[0105] In other words, the impulse means can be designed to give the impulse from the mobile element to a (preferably oscillating) piece of the oscillator, such as the balance or the balance plate.
