Mechanical stop and start system for a function and watch incorporating such system

Abstract

The invention relates to a mechanical stopping and starting system for a timepiece function, comprising: a mass mounted so as to be movable on a frame between a first end position and a second end position, the first and second end positions being defined respectively by a first stop and a second stop, the mass moving in a bistable manner under the effect of gravity, tensioning a spring between the first and second end positions and relaxing the spring between the second and first end positions.

Description

Technical Field

[0001] The present invention relates to the field of timepieces and to a mechanical system for stop and start functions. The expression "start function" is defined as the transition of a function from an initial rest state to a second active state, and the expression "stop function" is defined as the reverse transition from the active state to the rest state. Background Art

[0002] In the field of mechanical timepieces, functions with a rest or stopped state and an operating state are known. This is the case, for example, with chronographs or minute repeaters, which are activated by push-buttons or triggers. Some functions are also automatically activated by complex triggering systems, such as in hour striking mechanisms or alarm mechanisms.

[0003] Document US3541781 discloses a mechanism that makes it possible to detect whether the wearer is standing or sitting, and to measure the time spent in these positions. A lever is mounted so as to rotate freely and, depending on the position of the device, blocks or releases the escape wheel of the counting mechanism solely under the action of its weight. However, this mechanism is not very precise, and there is no defined position of the device at which the measurement is started or stopped.

[0004] The object of the present invention is to propose a command mechanism for a function that can be used in a mechanical watch, that is to say a watch that does not use electronic or electrical components, and which at least partially overcomes the drawbacks of the prior art. Summary of the Invention

[0005] More specifically, the invention relates to a mechanical system for stopping and starting a timepiece function, comprising a mass mounted movably on a frame between a first and a second extreme position defined respectively by a first stop and a second stop, said mass being displaced under the action of gravity, thereby loading a spring between the first and second extreme positions, and thereby releasing the spring between the second and first extreme positions, said mass being kinematically or directly connected to a control member for said function.

[0006] The force of the mass and of the spring is determined as a function of the force required to command the function and to displace the control member, and of a predetermined spatial orientation of the frame in which the mass is bistable displaced from one of its extreme positions to the other according to the resultant of the forces exerted by the spring and by gravity, the displacement of the mass from the first extreme position to the second extreme position being able to start the function via the control member, and the displacement of the mass from the second extreme position to the first extreme position being able to stop the function via the control member.

[0007] This definition of the invention extends to a command system for commanding a function of a timepiece, capable of occupying a first state and a second state, in particular an animation.

[0008] According to another aspect, the invention also relates to a watch comprising such a stop and start system. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Further details of the present invention will become more apparent upon reading the following description with reference to the accompanying drawings, in which:

[0010] - Figure 1 shows the definitions chosen for the axes of rotation to which the watch is subjected when worn,

[0011] - Figure 2 and Figure 4 is a diagram of a stop and start system according to a particular embodiment in a first extreme position and a second extreme position, respectively, and

[0012] - Figure 3 A watch comprising a system according to the invention for establishing the positions of reference axes and angles is shown. DETAILED DESCRIPTION

[0013] The object of the present invention is to propose a mechanical switch that makes it possible to start and stop a function on command, but without direct mechanical action or pressure applied to the switch. More specifically, the stop and start system according to the invention makes it possible to start and stop a function according to the spatial orientation of the system and, therefore, the spatial orientation of the watch incorporating the system. As will be understood below, various dimensions are possible, but a preferred embodiment is to dimension and arrange the system according to the invention so that a function starts when the wearer makes the usual movements to read the time when the watch is on his wrist, and stops when the wearer rotates his wrist, for example to return his arm to a more upright position.

[0014] More specifically, the system for the stop and start function according to the invention comprises a mass of the oscillating mass type, which is movably mounted on the watch frame between a first extreme position and a second extreme position. These latter positions are respectively defined by a first stop and a second stop, which may be elastic so as to dampen shocks.

[0015] The spring is connected to the mass. The connection between the spring and the mass is preferably direct, so that displacement of the mass has a direct effect on the winding of the spring. More specifically, when the mass is displaced under the action of gravity, following the movement of the part of the wearer that sets its motion, the spring is arranged to be loaded by the mass as it moves between a first extreme position and a second extreme position. Conversely, when the mass moves between the second extreme position and the first extreme position, the spring relaxes and, in this case, returns stored energy to the mass against the action of gravity.

[0016] The mass is connected to a control member for the functions described, either kinetically or directly. Advantageously, the connection between the mass and the control member is desmodromic. This connection can be of the meshing type, with a pinion or rack carried by the mass and meshing with the control member. The mass can also directly carry a magnet that can magnetically control functions such as visual animations, as will be described in detail below.

[0017] The mass (of the mass) and the force of the spring are determined as a function of the force required to command the function and to displace the control member. This system is also dimensioned according to a predetermined angular orientation of the watch, wherein the mass is displaced from one of its extreme positions to the other according to the resultant force exerted by the spring and gravity, and this displacement of the mass from one of said extreme positions respectively causes the activation or deactivation of the function via the control member.

[0018] In other words, in a first step, the force or torque required to respectively start or stop a function (pivoting the shuttle or column wheel of the chronograph, actuating a trigger lever, displacing a magnet, ...) is determined.

[0019] The orientation of the watch is also determined (wherein the desired function is activated or deactivated, respectively). In a preferred embodiment, the function is determined to be activated when the wearer raises the watch in the reading position to view it. Figure 1 As shown, angle α is defined as the angle of rotation about axis 9H-3H, angle β is defined as the angle of rotation about axis 12H-6H, and axis γ is defined as the angle of rotation about an orthogonal axis passing through the center of the dial. These three angles are zero when the watch is held horizontally and facing the wearer, with axis 9H-3H roughly parallel to the shoulder line. In the traditional position for reading the time, where it is desired to activate the functions, the following applies: α is between 30° and 35°, β = 0°, and γ = 0°.

[0020] Preferably, but not necessarily, it is also desirable to stop the function in a rotational position of the wrist that is different from the previous position. The risk of unintentional alternation between stopping and starting around a single direction is thus limited. Preferably, the stop orientation is defined so that α is between 15° and 18°, β=0°, γ=0°. It should be noted that the stop orientation is preferably different from the neutral orientation (where α=0°, β=0°, γ=0°) taking into account the starting point of the start. In order to distinguish the orientation of the watch used for the start and stop functions respectively, this hysteresis can be used in the calculation of the spring. This distinction makes it possible to avoid unintentional alternations between starting and stopping, which could occur if the watch swung around a single trigger and stop position.

[0021] Based on these factors, the stroke and weight (of the mass) are determined in order to generate the required torque.

[0022] However, the spring's stiffness and preload must also be determined. Its function is to maintain the mass in its first extreme position, against the force of gravity, unless the watch is positioned in the appropriate orientation. Beyond this orientation, the force exerted by gravity becomes greater than that of the spring, and the mass shifts, thus activating the function. When the mass is in its second extreme position, the spring similarly functions to return the mass to its first extreme position when the force exerted by gravity becomes less than that of the spring. The mass then ceases to function.

[0023] The sizing and calculation of the mass and the characteristics of the spring are within the purview of those skilled in the art and do not require a detailed description. To achieve the desired results, various parameter solutions exist, such as with heavier masses and stronger springs, so that the system can be activated and deactivated according to the desired specifications.

[0024] It is also possible to use an unbalanced mass mounted for rotational movement, similar to the oscillating masses used for automatic rewinding, some of which operate with limited angular travel. In this case, the imbalance, including the eccentricity of the mass, is taken into account, which has an impact on the torque provided. However, the mass can also have a linear or complex trajectory.

[0025] In this way, the start orientation and the stop orientation are predetermined. The mass is of the bistable type and is held in its first extreme position if the watch has not moved through the start orientation, and in its second extreme position if the watch has not moved through the stop orientation.

[0026] Unlike the present invention, the oscillating mass used in an automatic rewinding machine is not capable of stopping the rewinding function. In any case, even if it is necessary to allow for the absence of rewinding of the barrel in certain positions of the mass, in particular when the mass is stopped, the rewinding and non-rewinding positions are not predefined and do not correspond to a specific spatial orientation of the watch.

[0027] To reduce the shocks associated with the displacement of the mass and its interaction with the stop, the mass can be connected to a rate regulator. This latter can be an escapement, such as the friction-static escapement used in some striking mechanisms, or a centrifugal inertia brake of the type also used in striking mechanisms. Magnetic or oil-sump-based braking devices can also be used.

[0028] In order to offer the user the possibility of shunt-ing the switch and moving the watch without triggering a function, a blocking device for blocking the mass can be provided. This device is advantageously accessible from the outside of the watch. It can comprise a button or a screw that interacts directly or indirectly with the mass to block its movement, preferably in one of its extreme positions.

[0029] The system according to the invention can be arranged in the form of a self-contained module, comprising its own frame and mounted on a base movement. The mechanisms or components enabling the execution of the commanded functions can similarly be arranged on the frame or on the base movement. In this case, a kinematic connection or another type of connection, such as a magnetic connection, will be provided between the module and the base movement.

[0030] The system according to the invention can be used to command, that is to say start and stop, a function, the mechanism for allowing this function to be performed being provided in the watch.

[0031] Among the functions that can be controlled by the system according to the invention is visual animation. This can be mechanically commanded, for example, by releasing or blocking a barrel when the mass is in its first or second extreme position, respectively. This barrel can drive a Jacquemart-type automaton, usually by driving a cam against which a movable element is held pressed. By mounting a magnet on the mass or having a magnet driven by the mass, this magnet can drive the displacement of a paramagnetic or diamagnetic movable element capable of reacting to the displacement of the magnet by its own displacement. This displacement can be guided by the mounting of the movable element, for example in rotation or on a guide rail.

[0032] Figure 2 An example of a particular embodiment of the start and stop system according to the invention is shown. According to this example, the function to be commanded is an animation, controlled by the movement of a magnet.

[0033] This mass is an oscillating mass 10 mounted for rotational movement. It is equipped with teeth 100 that mesh with teeth 120 integral with a control member, in the form of a lever 12, mounted so as to be pivotable on the frame of the module or timepiece. Advantageously, teeth 100 and 120 are incomplete, that is, they are arranged on toothed sectors of less than 360°, as long as oscillating mass 10 is limited in rotation between its two extreme positions by two stops (not shown). In the exemplary embodiment, the reduction ratio between the teeth is set equal to -1.

[0034] The spring 14 is of the helical type and, in this example, acts on the control member via a first of its ends, at the axis of rotation of the lever. The other end is fixed to the frame.

[0035] At its end opposite the axis of rotation, the rod 12 carries a magnet 16. This magnet acts on a movable magnetic element, for example movable above the dial, so as to be visible to the user while the start and stop system is hidden under the dial.

[0036] When the watch is in a horizontal position, gravity acts parallel to the axis of rotation of the mass. As a result, the imbalance of the mass does not produce any torque on the axis.

[0037] Furthermore, in this example, spring 14 is preloaded in the clockwise direction. Consequently, spring 14 applies a clockwise torque to the lever, thereby transmitting a torque to oscillating mass 10 via the meshing connection that tends to cause it to pivot counterclockwise. However, in this position, oscillating mass 10 is in its first extreme position, resting against a stop, known as the upper stop (not shown). The system is thus balanced in its first stable position. The magnetic element, positioned by the magnet, is also in its first stable position. In this first position, it can be concealed behind the cover so as not to be visible to the wearer.

[0038] When the wearer of the watch rotates it around the axis 9H-3H ( Figure 3 ) When the mass is rotated by an angle α, the torque generated by gravity on the mass at the axis X gradually increases according to the following formula:

[0039] Torque of mass = d*m*gravity*sin(α)*cos(β)

[0040] where β is the center of mass relative to the axis 9h-3h( Figure 2 ) (with signs according to the rules of trigonometry).

[0041] The torque of the return spring (obtained at the center of rotation of the mass) is constant, while β remains the same and has the following value:

[0042] Spring torque = -K*(θ0+β0-β)

[0043] where β0 is the angle β when the mass is in its first stable position.

[0044] There is also a resistance moment for converting a function from a stopped state to a started state. In this example, this torque will be considered to be constant (with a value of Cresistif) and opposite to the direction of displacement.

[0045] Therefore, the balance of the torques applied to the mass is:

[0046] C=d*m*gravity*sin(α)*cos(β)-K*(θ0+β0-β)-Cresistif

[0047] When the torque is negative, the mass tends to rotate in a counterclockwise direction and thus remains abutted in the first stable position.

[0048] When sine(α) becomes greater than (β=β0), the torque becomes positive:

[0049] sin(α0)>(K*(θ0)+Cresistif) / (d*m*gravity*cos(β0)).

[0050] The angle at which the torque becomes positive is denoted as α0.

[0051] Once the result of the torques applied to the oscillating mass 10 has become positive, the torque generated by gravity will be greater than the resisting torque of the functional and return springs. As a result, the mass will pivot in the clockwise direction around its axis (β will decrease). As long as the oscillating mass 10 has not reached its second extreme position ( Figure 4 ), it will move against a stop called the lower stop (not shown), or until the torque caused by gravity becomes less than the resisting torque again.

[0052] In fact, if the angle α of the watch does not change, only the angle β will change, and the magnitude of the torque generated by gravity will be sought to increase faster than that of the spring (through a judicious choice of the various parameters of the mass and the spring). Thus, once the mass begins to move, the torque increases solely with the displacement of oscillating mass 10, and the transition from the first extreme position to the second occurs continuously, without passing through a stable intermediate position (without changing the angle of the watch), and the mass is therefore bistable. The magnetic element is also in a second stable position. In this second position, it can be seen by the wearer.

[0053] As long as the angle of the watch remains constant, the system remains in equilibrium with the oscillating mass 10 in its second stable position. However, the equation for the torque has changed, since the sign of the function's resisting torque has now changed (to switch the function from the start state to the stop state this time, the mass must rotate in the counterclockwise direction).

[0054] We have:

[0055] C=d*m*gravity*sin(α)*cos(β)-K*(θ0+β0-β)+Cresistif

[0056] When this torque is positive, the oscillating mass 10 tends to rotate in the clockwise direction and thus remains in abutment in the second stable position.

[0057] When sine(α) becomes smaller than (β=βF), the torque becomes negative:

[0058] sin(αF)<(K*(θ0+β0-βF)-Cressistif) / (d*m*gravity*cos(βF)).

[0059] The angle at which the torque becomes negative is denoted as αF.

[0060] Once the resultant of the torques applied to the mass has become negative, the torque generated by gravity will be less than the resisting torque of the power and return springs. Consequently, the oscillating mass 10 will pivot counterclockwise about its axis (β will increase). The mass will continue to move until it returns to its first extreme position, or until the torque generated by gravity again becomes greater than the resisting torque.

[0061] In fact, if the angle of the watch does not change, only e will change, and the progression of the torque generated by gravity will be sought to decrease more rapidly than that of the spring (by a judicious choice of the various parameters of the mass and the spring). In this way, once the mass begins to move, the torque only decreases with its displacement, and the transition from the second extreme position to the first occurs continuously, without passing through stable intermediate positions (without changing the angle of the watch), and the mass is therefore in fact bistable.

[0062] It should be noted that in the case of visual animations, the concept of the stop and start functionality must be understood broadly, as corresponding to the first and second states of the visual animation. It is worth mentioning that the term "command system" can be used as an equivalent to the term "stop and start system".

[0063] Similar to the visual animation driven by the barrel, this function can also be a striking mechanism, whose triggering can be completed by the striking mechanism. When the barrel is in its first extreme position or its second extreme position, respectively, the barrel is released or blocked according to the positioning of the mass.

[0064] In both examples of barrel implementations mentioned, the barrel is rewound by a rewinding mechanism, specifically via the movement's mainspring barrel. This rewinding can be manual or automatic. Similarly, by using a barrel suitable for supplying energy via two power take-offs, it is possible to power the animation or striking mechanism via the movement's barrel.

[0065] Via a kinematic connection of the meshing type (pinion or rack), it is also possible to move the wheel or pinion by a chronograph control member, such as a set of shuttles or a column wheel of the chronograph. The zeroing phase can advantageously be achieved by a push-button acting solely on the control member and the conventional zeroing element (hammer...).

[0066] The kinematic connection to the unbalanced mass can also displace at least one movable shutter above or below the main dial, sub-dial, or part of the dial to modify the appearance of the watch or to allow a particular display to be seen. Polarized glasses can be used and displaced via the movable shutter(s).

[0067] This shutter can also be displaced by releasing the barrel, similar to what has been described above.

[0068] Thus, the system according to the invention makes it possible to command a function by starting and stopping it, or by commanding it to transition from the first state to the second state, or vice versa, when the watch is in a first spatial orientation and a second spatial orientation, respectively. These specific spatial orientations correspond to the first and second extreme positions of the mass. These positions are defined, and thanks to the bistable nature of the displacement of the mass, the transition from one state of the function to the other is precise, corresponding to a specific spatial orientation.

[0069] A person skilled in the art may modify the above description without departing from the scope of the invention as defined in the claims. They may define the start and stop orientations, the type, force and preload of the springs and the connection between the mass and the control system.

Claims

1. A mechanical system for stopping and starting the functions of a timepiece, said mechanical system comprising: a mass (10) which is movably mounted on the frame between a first extreme position and a second extreme position defined by a first stopper and a second stopper, the mass being displaced under the action of gravity so as to load the spring (14) between the first extreme position and the second extreme position and to relax the spring between the second extreme position and the first extreme position, The mass is kinematically or directly connected to a control member (12) for the function, The force of the spring (14) and the mass (10) are determined as a function of the force required to command the function and to displace the control member (12), and a predetermined spatial orientation of the frame in which the mass is bistable displaced from one of its extreme positions to the other according to the resultant of the forces exerted by the spring and gravity, the displacement of the mass from the first extreme position to the second extreme position being able to start the function via the control member (12) and the displacement of the mass from the second extreme position to the first extreme position being able to stop the function via the control member (12).

2. The system according to claim 1, wherein: The mass is mounted so as to be movable in rotation and is unbalanced.

3. The system according to claim 1, wherein: The mass is connected to a speed regulator.

4. The system according to claim 3, characterized in that The speed regulator is an escapement, an inertia brake, or a viscous friction device located in a groove.

5. The system according to claim 1, wherein: The system includes means for stopping the proof mass.

6. The system according to claim 1, wherein: The control member carries a magnet.

7. The system according to claim 1, wherein: The spring is calculated such that the orientations of the frame that trigger the activation and deactivation of the function, respectively, are different.

8. The system according to claim 1, wherein: Elements enabling the implementation of the functions are mounted on the frame.

9. A watch comprising a system according to claim 1 and a mechanism enabling said function, wherein: The mass is transferred from its first extreme position to its second extreme position, and vice versa, when the watch is in the first spatial orientation or in the second spatial orientation, respectively.

10. The watch according to claim 9, characterized in that The first spatial orientation and the second spatial orientation are different.

11. The watch according to claim 10, characterized in that In the first spatial orientation, the watch has an angle α between 30° and 35°, β=0°, γ=0°, and in the second spatial orientation, the watch has an angle α between 15° and 18°, β=0°, γ=0°, The angle α is the rotation angle of the watch around the axis passing through positions 9H and 3H of the dial, α is equal to 0° when the dial is horizontal, the angle β is the rotation angle around the axis 12H-6H, and the angle γ is the rotation angle around the orthogonal axis passing through the center of the dial.

12. The watch according to claim 9, characterized in that The system comprises means for blocking the mass, said means being accessible from the outside of the watch.

13. The watch according to claim 9, characterized in that The mechanism is selected from a timing mechanism, a time reporting mechanism, and a visual animation mechanism.

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