Classifications

• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B17/00—Mechanisms for stabilising frequency
  • G04B17/04—Oscillators acting by spring tension
  • G04B17/045—Oscillators acting by spring tension with oscillating blade springs
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B15/00—Escapements
  • G04B15/10—Escapements with constant impulses for the regulating mechanism
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B15/00—Escapements
  • G04B15/14—Component parts or constructional details, e.g. construction of the lever or the escape wheel

Definitions

• the present invention relates to a watch exhaust, that is to say a mechanism for maintaining and counting the oscillations of a watch regulator.
• the present invention more particularly relates to an escapement comprising a bistable elastic member receiving energy from a drive member, for example a cylinder, and communicating it to the regulator.
• a bistable elastic member receiving energy from a drive member, for example a cylinder, and communicating it to the regulator.
• An escapement of this type is described in patent applications WO 99/64936, WO 2009/1 18310 and CH 705674.
• the bistable elastic member is a leaf spring working in buckling mode.
• the leaf spring is fixed at both ends to recesses or pivoting members, and its midpoint is kept aligned with said two ends. The distance separating the two recesses is such that the leaf spring undergoes a compression which forces it to deform according to a second mode buckling.
• the leaf spring thus has two convexities of opposite directions on either side of its midpoint.
• the leaf spring can occupy two stable states, the transition from one to the other of these stable states being effected by reversing the direction of the two conve
• an armature lever acting symmetrically in the region of the two convexities deforms the leaf spring from a first of its stable states to a metastable state close to an unstable state corresponding to a fourth mode buckling, to arm the leaf spring.
• a trigger rocker located in the area of the midpoint acts on the leaf spring to make it exceed its unstable state and make it switch to its second stable state by releasing its energy.
• the armrest lever is alternately actuated by two escape wheels integral with escape gears which mesh with the last mobile of the finishing gear of the timepiece.
• the trigger rocker cooperates with a balance-spiral regulator and comprises for this purpose a fork of the same type as conventional anchor forks.
• the exhaust wheels comprise at their periphery cams for arming for actuating the rocker arming. These armature cams end with locking stops.
• the arming phase of the leaf spring by the arming lever ends when it is blocked by one of the locking stops of the escapement wheel with which it cooperates, which keeps the leaf spring in its position. metastable state and immobilizes the two escape wheels, the finishing gear and the armature rocker.
• the deformation of the leaf spring from its metastable state to its second stable state under the action of the plate pin and its detent causes a rotation of the armature rocker which unlocks the escape wheels and causes the rocker to arming in contact with the other escape wheel to start a symmetrical cycle of the previous, after the impulse given to the plateau pin.
• the present invention aims to remedy these drawbacks, or at least to mitigate them, and proposes for this purpose a clockwork escapement comprising a bistable elastic member, an armature rocker arranged to arm the bistable elastic member during phases of rotation. arming, and a trigger rocker arranged to be driven by an expansion of the resilient bistable member after each arming phase to communicate a pulse to a regulator, characterized in that it comprises a single escape wheel for driving the rocking arm during the winding phases, the escapement comprising a winding member arranged to cooperate with the winding elements of the rocking arm, in the manner of a gear, to make rotate the armature rocker alternately in opposite directions.
• the armoring elements are defined by an inner wall of a portion of the armature rocker which surrounds the armoring member.
• said inner wall follows over substantially 360 ° the trajectory of the crown of a tooth of the armoring member in a reference frame connected to the armature rocker during the rotation of the armoring member, in order to abut against the arming member in case of shock and thus secure the position of the rocker arming.
• the elements of arming are for example pins.
• the armoring member is for example a star.
• the trigger rocker is arranged to cooperate with the bistable elastic member in the region of a midpoint of the bistable elastic member and the armature rocker is arranged to cooperate with the bistable elastic member on both sides. another of said area.
• an escapement for a watch movement comprises an escapement wheel 1, a bistable leaf spring 2, a winding lever 3 and a trigger rocker 4.
• the escapement wheel 1 rotates about an axis A, in the direction indicated by the arrow F1, under the action of the drive member of the movement, typically formed by one or more barrels.
• the escapement wheel 1 comprises an escape pinion 5 which meshes with the movement finishing gear, a winding member 6 which, in the example shown, is in the form of a star, and a wheel of locking 7 having at its periphery inclined teeth 8.
• the escape gear 5, the winding star 6 and the locking wheel 7 are coaxial and integral.
• the winding star 6 and the locking wheel 7 can be in one piece.
• the armature rocker 3 and the rocker trigger 4 pivot about the same imaginary axis B which corresponds to the midpoint of the leaf spring 2, but are free to rotate relative to each other.
• the imaginary axis B is for example the axis of a rod (physical axis) driven into the armature rocker 3, pivoting in bearings of the frame of the movement and around which pivots the trigger rocker 4.
• the latches 3, 4 could be mounted on respective axes offset relative to each other, like the armature and trigger rockers described in the patent application WO 99/64936.
• the latches 3, 4 may not be mounted on physical axes but be guided around the same imaginary axis or two respective imaginary axes by flexible guiding systems.
• the leaf spring 2 is integral with the trigger rocker 4 and consists of two elastic blades 2a, 2b each having an end joined to the trigger rocker 4 and another end joined to the frame of the movement. Said other end of each elastic blade 2a, 2b can be joined to the frame of the movement via an outer frame (not shown) surrounding the leaf spring 2 and fixed to said frame, outer frame which can be integral with the spring -lame 2, as described in patent applications WO 2009/1 18310 and CH 705674.
• the leaf spring 2 may also be an insert relative to the trigger rocker 4 and the outer frame.
• the leaf spring 2 has two convexities of opposite directions on either side of its midpoint and can move from a first stable state to a second stable state by reversing the direction of each of the two convexities.
• the leaf spring 2 is either prestressed so as to work in buckling or preformed for, in the state of rest, already have two convexities as described in the international patent application WO 2017/032528 of the present applicant.
• the outer frame is deformable to allow buckling of the leaf spring 2.
• the outer frame is rigid.
• the armature rocker 3 comprises two arms carrying at their ends two pins 3a, 3b engaged in eyelets (not shown) of the two resilient blades 2a, 2b respectively.
• the armature rocker 3 further comprises a ring-shaped portion 9 which surrounds the winding star 6.
• the inner wall 10 of this part 9 has winding elements 1 1, 12 (see FIG. ) constituted by lugs, and is further irregularly shaped to fulfill a safety function against shocks, that is to say to prevent a rotation of the armature rocker 3 beyond a certain clearance when a rotary or linear shock received by the watch movement.
• the inner wall 10 of the part 9 follows on substantially 360 ° the trajectory of the vertex of any one of the teeth of the winding star 6 in a reference linked to the armature rocker 3 during the rotation of the winding star 6 and oscillations of the armature rocker 3 which result, to abut against the winding star 6 in case of shock.
• the positioning of the armature rocker 3 is guaranteed by a small clearance, predefined, and thus prevents the armature rocker 3 triggers the tilting of the leaf spring 2 inadvertently.
• the trigger rocker 4 comprises an inlet arm 13 terminated by an inlet spout 14 and an outlet arm 15 terminated by an outlet spout 16. These inlet and outlet spouts 14, 16 are arranged to cooperate with the teeth 8 of the locking wheel 7, as will be explained below.
• the trigger rocker 4 also comprises a rod 17 ending in a fork 18 similar to that of a traditional anchor, comprising a first horn 19 and a second horn 20.
• the fork 18 is arranged to cooperate with a plateau pin 21 worn by a large plate 22 coaxial and integral movement regulator.
• the regulator (not shown) oscillates around an axis C, for example of the spring-balance type but can also be an oscillator without physical axis, with flexible blades.
• First and second limiting abutments 25, 26 fixed relative to the frame of the movement limit the angular movement of the trigger rocker 4. These limit stops 25, 26 are for example in the form of pins, as shown, or 'étoqueaux. They can be integral with the outer frame of the leaf spring 2.
• the escapement according to the invention operates according to cycles each corresponding to an oscillation (two alternations) of the regulator.
• Each cycle comprises two half-cycles.
• Each half-cycle corresponds to an alternation of the regulator and includes the following phases: arming, locking, relaxation.
• the arming phase of the first half-cycle begins when a tooth 6a of the winding star 6 encounters a first, 1 1, winding elements 1 1, 12 of the armature rocker 3 (cf. figure 1 ). By continuing its movement, the tooth 6a pushes this first armoring element 1 1, which pivots the armature rocker 3 about its axis B in the direction indicated by the arrow F2. This movement of the armature rocker 3 arms the leaf spring 2 by passing it from a first stable state to a metastable state close to an unstable state. This deformation of the leaf spring 2 is imperceptible in the area of the midpoint, so that the trigger rocker 4 remains stationary.
• the leaf spring 2 then releases the energy accumulated during the arming by switching to its second stable state, which is the opposite of the first stable state. This is the relaxation phase.
• This sudden deformation of the leaf spring 2 rotates the trigger rocker 4 in the direction F2.
• the inlet nose 14 of the trigger rocker 4 leaves the tooth 8a of the locking wheel 7, overcoming the force pressing against said input spout 14 under the action of the drive member of the movement, and unlocks the escape wheel 1, then the inner face of the second horn 20 communicates a pulse to the plateau pin 21 and therefore to the regulator (see Figure 4).
• the expansion phase ends when the trigger rocker 4 comes into abutment against the second limit stop 26 (see Figure 5) in the second stable state of the leaf spring 2.
• the locking / unlocking of the mobile escapement 1 in the present invention is carried out directly by the trigger rocker 4 by means of the inlet and outlet nozzles 14, 16, so static, rather than by the armature rocker controlled by the leaf spring itself controlled by the trigger rocker as in the state of the art.
• the leaf spring 2 is only used for the pulse to the regulator. This allows to unlock the mobile escape 1 early enough, that is to say before the regulator reaches its equilibrium position, to let the leaf spring 2 free to provide its momentum when the regulator is close to its equilibrium position . The moment of the beginning of the pulse can therefore be precise, which favors the isochronism of the regulator.
• a single mobile escape 1 comprising the elements 1 1, 12 eliminates the need to index two mobile exhaust relative to each other, so facilitates assembly , and reduces clutter and inertia.
• the cooperation between the teeth of the winding star 6 and the winding elements 1 1, 12 generates little or no friction, unlike the winding cams of the mechanism according to WO 99/64936, WO 2009/1 18310 and CH 705674, which slide on pins carried by the rocker arming.
• the cooperation between the winding star 6 and the winding elements 1 1, 12 is similar to that of a gear, the winding star 6 exerting on the inner wall 10 a tangential force.
• the winding star 6 and the locking wheel 7 could form a single piece on a single level.
• the teeth of the star 6 would ensure in certain positions the arming and in other positions the locking.
• the bistable elastic member that constitutes the leaf spring 2 could be formed of a single elastic blade 2a or 2b and the armature rocker 3 could comprise a single arm cooperating at its end with the elastic blade.
• the bistable elastic member could comprise a plurality of leaf springs each comprising one or more elastic blades.
• the mobile escape 1 could be located on the other side of the regulator or be coaxial with said regulator (that is to say, the C axis).

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Cited By (1)

Citations (6)

• 2017
  • 2017-06-20 EP EP17733910.8A patent/EP3475765B1/de active Active
  • 2017-06-20 WO PCT/IB2017/053668 patent/WO2018002773A1/fr unknown

Patent Citations (6)

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