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
  • G04B17/20—Compensation of mechanisms for stabilising frequency
  • G04B17/28—Compensation of mechanisms for stabilising frequency for the effect of imbalance of the weights, e.g. tourbillon
  • G04B17/285—Tourbillons or carrousels

Definitions

• the present invention relates to movements for so-called mechanical timepieces. It relates more particularly to a movement which comprises a frame defining a reference plane hereinafter called the movement plane and on which are mounted: - a source of mechanical energy, - a gear train driven by said energy source and arranged so as to be able to support time display means, - a time base comprising two balance springs and two escapements, and - a differential gear ensuring a kinematic connection between the gear train and the escapements.
• the daytime running of the watch is equal to the average of the daytime running of the two balance-springs.
• the differential independently supplies the exhausts that maintain the movement of the two balance springs.
• a coupling may appear, so that, cyclically, the amplitude of one pendulum can decrease while that of the other increases, and this in proportions that can be important. If therefore, one does not want to fear that a pendulum will rebound, it is necessary that the amplitude is considerably reduced, which goes against the desired goal.
• the two balance springs are mounted on the same tourbillon cage, which carries two escapements and a differential ensuring the supply of the two escapements. In this case also, the risk of beating exists. Furthermore, as the two pendulums are arranged side by side, their cumulative diameters cannot exceed the radius of the movement.
• the object of the present invention is to provide a movement provided with two balance springs which can be of large diameter, without risk of coupling.
• the time base comprises two vortices, each provided with a cage carrying an escapement and a balance-spring. These cages are driven at least medially in rotation by the differential gear.
• the term tourbillon is to be taken in the broad sense, also covering carousels. With such a configuration, the fact that the hairsprings are each secured to a tourbillon cage, which is rotatably mounted on the frame, makes coupling practically impossible.
• each balance is mounted on a cage, it follows that its diameter is only very little smaller than that of the cage.
• the regulating quality of a pendulum is all the better the larger its diameter, because the growth of the moment of inertia as a function of the diameter is faster than that of the weight. Thus, the precision of the movement can be improved significantly.
• the tourbillons In order to reduce the distance between the horizontal and vertical positions, at least one of the tourbillons has a cage which pivots about an axis which is not orthogonal to the plane of movement. In this way, whatever the position of the timepiece, the two axes of the pendulums will never be vertical simultaneously, which means that, in addition to the advantages mentioned above, the gait differences between the different positions of the watch are noticeably weaker.
• the tourbillon comprising a cage whose axis is non-orthogonal to the plane of movement comprises a second cage, pivotally mounted on the frame around an axis orthogonal to the plane of movement and in which the first cage pivots.
• the movement according to the invention comprises, in a conventional manner, a frame consisting of a plate 10 and at least one bridge 11 and defining a reference plane called the plane of movement, on which the various cogs, levers and rockers pivot, around axes perpendicular to this plane.
• the figure shows a medium wheel 12, part of a gear train driven by a barrel which it is useless to represent.
• This wheel meshes with a mobile performing one revolution per minute and comprising a shaft provided with a pinion 13 engaged with the average wheel 12 and a wheel 14.
• a seconds hand 15 is driven out on one of the ends of the tree.
• the latter carries, in addition, mounted free in rotation, a first mobile formed by a pinion 16 whose function will appear further on and a wheel 17 meshing with a pinion 18 secured to the cage 19 of a first vortex 20.
• This vortex pivots in the frame around an axis AA perpendicular to the plane of movement.
• the cage 19 carries an escape wheel 21 which drives an anchor and, by it, a balance-spring, these last two components not being shown to avoid overloading the drawing. More complete information concerning this type of tourbillons can be found in the work entitled “Clockmaking theory”, Chs-A. Reymondin et al, ISBN 2-940025-10- X.
• a wheel 22, having the same diameter and the same number of teeth as the wheel 17, is also mounted to rotate freely on the shaft 13. It meshes with the pinion 23 of a first cage 24 which comprises a second vortex 25.
• the pinion 23 and the cage 24 pivot in the frame around an axis BB perpendicular to the plane of movement.
• a second cage 26 is pivotally mounted on the first cage 24, around an axis CC making an acute angle, typically 30 ° with the axis BB.
• the cage 26 carries an escape wheel 27 which drives an anchor and by it a balance-spring, these last two components not having been shown in the drawing to avoid overloading it.
• the structure and operation of a tourbillon of this type are described in detail in patent application WO / 03017009 filed in the name of the applicant.
• the wheel 22 carries a satellite comprising a first satellite pinion 28 mounted on one face thereof, in engagement with the wheel 14 and rigidly coupled, by means of a screw 29, to a second satellite pinion 30 disposed on the 'other face of the wheel 22 and meshing with the pinion 16. It will be noted that these two planet gears have substantially different diameters.
• the mechanism formed by the shaft 13, the wheels 14, 17 and 22 and the pinions 16, 28 and 30 constitutes a differential gear 31 which makes it possible to drive the cages 19 and 24 of the two vortices 20 and 25 at their own pace. Indeed, each of the cages turns in jerks, each time the escapement gives an impulse to the balance. This therefore amounts to saying that, during each driving pulse, the differential train turns and drives one or the other of the cages, or even both simultaneously.
• the differential train is itself driven by the medium wheel 12 which is driven by the barrel.
• the average wheel 12 acts, through the pinion 13 and the wheel 14, on the pinion-satellite 28. It thus generates torques applied one on the pinion 16 by the pinion-satellite 30, the other directly on the wheel 22, because the pinions 28 and 30 do not have the same number of teeth.
• the vortices can both be of the same type as the vortex 20 with their axes parallel to each other and perpendicular to the plane of movement. They can also both be of the same type as the tourbillon 25, that is to say each comprising two cages, one of which is not orthogonal to the plane of movement. It is also possible that the cages pivot directly in the frame, on axes which are not orthogonal to the plane of movement.
• the periods and directions of rotation of the vortices can be the same or different, defined by the gear ratios of the differential.
• balance springs such as their period of oscillation or their moment of inertia may be similar or different.
• an intermediate train will advantageously be interposed between the differential wheel and the tourbillon pinion, so that the angle traveled by the mean wheel 12 is the same for the two vortices, so that the energy supplied to each of the vortices is the same.
• the tourbillon cages have the same frequency of rotation, these will advantageously be equipped with means for identifying their position, which will make it possible to independently determine the progress of each of the tourbillons, and thus facilitate the adjustment of the movement.
• the same principles are also applicable to a movement which would include more than two balance springs, providing, for example, a cage of two pendulums, as described in the catalog mentioned above, and a second cage comprising a single pendulum. It is even possible to equip the movement with a third tourbillon.
• one and / or the other of the vortices could also be of the type with two or three cages, for example orthogonal.
• the movement is equipped with at least two tourbillons, it is possible to improve its precision without the risk of fluttering phenomena, while giving it a prestigious character.

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• Transmission Devices (AREA)

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• 2003
  • 2003-10-31 CH CH18652003A patent/CH694833A5/fr not_active Application Discontinuation
• 2004
  • 2004-10-18 DE DE602004007045T patent/DE602004007045T2/de not_active Expired - Lifetime
  • 2004-10-18 EP EP04761967A patent/EP1706796B1/de not_active Expired - Lifetime
  • 2004-10-18 WO PCT/CH2004/000627 patent/WO2005043257A1/fr active IP Right Grant

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