Patent Grant
11822290
The invention object is a watchmaking tourbillon whose cage contains two oscillators.
The tourbillon mechanism was invented by Abraham Louis Breguet in 1810. In such a mechanism, the escapement and the balance-spiral are set in a rotational motion inside a cage. Initially, this mechanism aimed to even out the positions when the watch was worn vertically. This way the static and dynamic balance defects would be leveled. Practically, the chronometric results for a wristwatch fitted with a tourbillon are subpar and do not compensate for the excess works such a device requires. However, the horological tourbillon is a staple of watchmaking tradition and is visually fascinating.
The basic principle of a tourbillon is to fit an entire escapement and it's oscillator inside the fourth wheel. The escapement pinion rotates against a fixed wheel. At each impulsion, the escapement releases the fourth wheel that carries the cage and all the components held within. The inertia of the cage is of utmost importance: if it is too heavy, it's acceleration will be diminished and the impact when it stops will be too strong.
At each impulsion, the balance wheel receives a little bit of energy from the escapement, which then propels it alternatively clockwise and anticlockwise. However the cage rotation steps occur during the impulses and only in one direction.
The spiral-balance that is used as an oscillator is attached to the cage by a stud. The stud links the terminal curve of the spiral to the balance bridge.
During one impulsion, the cage and the balance wheel motions are in the same direction. The balances receives one impulsion from the lever and one impulsion from the cage through the terminal curve of the spiral.
During the next impulsion, the cage and balance wheel motions are in opposite direction. The balances receives one impulsion from the lever and one opposite impulsion from the cage through the terminal curve of the spiral.
As a result, with a conventional tourbillon configuration, half of the impulsions will lead to a higher-than-average amplitude, and the other half will lead to correspondingly diminished amplitude. The function is asymmetrical regarding the balance wheel zero position.
The influence of the cage, while being problematic, can be compensated by tweaking the components of the balance. However the influence of the balance movement on the cage dynamics is uncontrollable.
When the escapement sends an impulsion to the balance in the same direction as the cage motion, the cage is subject to an opposite reaction, which slows down the motion of the cage and minimizes the stop shock.
When the escapement sends an impulsion to the balance in the opposite direction to the cage motion, the cage is subject to an opposite reaction, which speeds up the motion of the cage and creates an excess stop shock.
From the escapement standpoint, the asymmetry between two alternations can be a problem during the balance wheel's free angle.
After an impulsion in the same direction as the cage, the terminal curve of the spiral creates a pressure effort on the cage. This effort is being transmitted on the escapement through the pressure of the escapement pinion on the fixed wheel, which is not problematic and enhances the drawing security.
The drawing effect is a safety function in the lever escapement. Using the angle formed by the lever pallets and the escape wheel teeth, the pressure from the escape wheel teeth draws the lever fork away from the balance axle in case of a shock. This security function minimizes the perturbation duration if the lever dart were to touch the small plate of the balance axle, and quickly brings back the lever stem in contact with the limiting pins.
After an impulsion in the opposite direction to the cage, the terminal curve of the spiral creates a traction effort on the cage. This traction effort goes against the pressure applied on the cage by the gear train, and tends to push the cage backwards. Therefore the pressure from the escapement pinion teeth on the fixed wheel teeth will diminish, which in turns diminishes the pressure from the escape wheel teeth on the lever pallets. The drawing effect is diminished.
As a result, in a conventional tourbillon cage with a spiral balance oscillator and an lever escapement, there are perturbations from the balance to the cage, and from the cage to the balance. Some strong perturbation risks also occur every other alternation because the drawing effect diminishes.
To this day, the closest execution that could correct these defects is the H2 resonance tourbillon from Beat Haldimann.
This invention aims to develop a horological tourbillon device that could alleviate the usual tourbillon cage perturbations.
To achieve this the present invention encompasses a horological tourbillon comprising:
According to another characteristic, the oscillator's axis are colinear to a main axis, which is the cage axis,
According to the invention, this invention has two main advantages:
When the two balances are working, they both oscillate synchronously and in opposite directions. This way the sum of the rotational motion of both oscillators regarding to their rotation axis is always zero. The resulting torque applied by the balances on the cage is consequently zero.
If the two balances are coupled for synchronization, the perturbation applied to the balances by the cage is spread over the two balances. Each oscillator therefore is less perturbated than if it were alone.
According to another advantageous characteristic the two spirals and balance wheels are identical to guarantee that inertias are as close as possible.
According to another advantageous characteristic the spirals are located between the balances, to minimize the space between the spirals and increase system capacity.
According to another advantageous characteristic the spirals coiling has the same direction to allow synchronicity of the development of the spirals during their function.
According to another advantageous characteristic the two escapement assortments are identical within a planar symmetry, to make the balancing of the cage easier.
According to another characteristic the oscillators may have a spiral with flat terminal curve or a Breguet overcoil.
According to another characteristic the escapements are of any type (swiss lever, trigger escapement, etc.) as long as the two escapements are identical.
In other terms the two oscillators are mounted head-to-toe, one being on the top of the medial plane, the other being below.
As previously indicated the escapement mobiles are placed according to an axial symmetry regarding to the cage main axis,
According to another characteristic the cage is made of a cage belt wheel that constitutes the medial plane with the two half-cages being on each side. Each half cage being made of plates and bridges.
According to another characteristic the differential has flat gears comprising:
According to another characteristic the main tourbillon axis and the differential axis are parallel.
The differential frame being made of a base carrying two colinear pivots, one of them carrying the input pinion. The frame carrying two plates with rotating points in which the satellites rotate.
According to another characteristic each satellite is made of one short pinion and one long pinion. The satellites in each pair are mounted head-to-toe, their rotation axis being parallel.
The satellite pairs being mounted in the differential following a 180 degrees symmetry according to the differential frame rotating axis, the long pinion of one satellite is cut so as to mesh with the tubular output pinion and with the short pinion of the other satellite in the same pair, the short pinion of each satellite is cut so as to mesh with the long pinion of the other satellite in the same pair, while avoiding to mesh with any output pinion.
In other terms the satellite pinion is made of:
According to another particularly advantageous characteristic the differential frame has an equatorial groove to allow the cage belt toothing to pass and thus reducing the encumbrance on the equatorial plane. All the differential satellites also exhibit a similar equatorial groove.
In other terms, to allow the reduction of distance between the differential axis and the tourbillon cage axis, the differential has a hourglass shape, so do the differential satellites.
As a result the horological tourbillon according to the invention is a particularly compact configuration that allows for a considerable enhancement of the mechanism regulation.
The present invention will be described hereafter in a more detailed fashion using various realization modes shown in (annexed) schematics in which:
According to the horological tradition the function of the mechanism will be described from the source of the power to the oscillator. As a result the description of the relationship with the differential D is the opposite of some terminologies regarding the differential outputs.
The speed of the horological mechanism MH is dictated by the regulation system made of the double tourbillon TD and it's two combined oscillators. The two oscillators have a frequency that is identical in theory, but necessarily different practically, which implies that this difference needs to be compensated to void the mechanism stoppage. The speed co dictated by the double tourbillon TD is the speed average between the speed ω1=(ω+δω) and ω2=(ω−δω) of respectively the two oscillators OSa,b since the differential frame will rotate at a speed (ω1+ω2)/2=ω.
The horological tourbillon T according to the invention comprises the double tourbillon TD itself made of a cage CC rotating around the axis ZG, and led by the horological mechanism MH by a gear train linked to the cage belt wheel EC of the cage CC.
The cage belt wheel RC defines the cage medial plane CC. On each side of this plane is installed an oscillator OSa, OSb, respectively. These oscillators are constructed and regulated so that their frequencies are as close as possible to each other, However the two oscillators frequencies can never be completely identical.
This slight discrepancy around the average frequency is taken into account by the differential. We will name ω1=(ω+δω) the speed of one of the oscillators, and ω2=(ω−δω) the speed of the other. This frequency difference is being translated by a shift in the speed of the compensation wheels, which in turn affect the speed of the differential outputs.
The average of those two speeds is necessarily the speed co dictated by the regulation system to the horological mechanism MH.
Each oscillator OSa, OSb is fed by an escapement mobile MEa,b carried by the cage CC, itself being fed by the compensation wheel RFa, RFb, each being linked to one of the two differential D outputs through an intermediate wheel ERFa, ERFb, respectively.
The gearing between an escapement mobile Mea,b and the corresponding compensation wheel RFa,b is not detailed, given that this structure clearly appears in
In order to simplify the drawing, the escapement mobiles MEa and MEb do not enter in the cage CC alongside the axis ZC, but are rather shown on the sides of the cage CC. The compensation wheels RFa, RFb are coaxial to the CC cage axis ZC. This does not modify the linkage between the escapement mobiles MEa, MEb to their corresponding compensation wheel RFa, RFb.
The differential D is composed of a frame CH set in motion around it's axis ZD, and carry the output mobiles Sa, Sb each carrying an output pinion Pa, Pb coaxially to ZD. The two output pinions Pa, Pb are linked by two satellites STa, STb carried by the differential frame CH. The satellites reverse the rotation motion of the two pinions Pa, Pb according to the conventional function of a differential.
In the case of the schematics in
Each satellite STa, STb is made of two pinions (ST1a long, ST2a short) and (ST1a long, ST2a short) each on a single axis ASa, ASb carried by the frame CH.
The number of teeth for the pinions ST1a . . . ST2b being the same, the combination of the two satellites STa and STb reverses the transmitted motion from one satellite to the other. As a result when the frame CH rotates with speed co the outputs rotate at a speed +/−δω relatively to the frame.
The outputs Sa, Sb receive the motion ω1, ω2 from the two oscillators and convey them to the two pinions Pa, Pb; because each pair of satellites is carried by the frame CH, the frame is set in rotation around the axis ZD at the average speed ω=(ω1+ω2)/2. The relative differences in rotation speed +δω and −δω from the two pinions Pa, Pb ends up being compensated.
The horological tourbillon TD dictates its rotation speed co to the rest of the mechanism MH.
For the sake of clarity of
In order to equally transmit the pressure efforts to the output pinions Pa, Pb, the satellite pair STa, STb is supplemented by a second identical pair ST′a, ST′b, symmetrically placed according to the axis ZD.
To simplify the representation of the horological tourbillon T, given the identity of shapes and symmetries, the components will bear their numerical references appended by the suffix (a) or (b).
The different parts of the double tourbillon TD will be described separately in
The wheel 10 has a belt toothing 101 for its gearing. It carries the escapement plate 11a using the pillars 161. The escapement plate 11a carries the escapement bridge 13a.
The lever bridge 12a is carried by the escapement plate 11a and the cage pivot 14a is mounted on the lever bridge 12a.
The cage elements are mounted in a rigid way. The escapement plates 11a,b are carried by the shared wheel 10 via pillars 16. The lever and escapement bridges (respectively 12a,b and 13a,b) are mounted on the escapement plate 11a,b via pillars 16. The cage pivots 14a,b are mounted on the lever bridges 12a,b.
The bridgework shown on
A collet 42a carrying a spiral 45a is fitted on the cylindrical portion of the axis 40a. The spiral 45a comprises an Archimedean flat spiral portion 450a and a Breguet overcoil 451a. The terminal curve is attached to a stud 46a held in a stud holder 15, linked to the cage wheel structure 10 (
The lever 3a is made of a base 30a, an entry pallet 31a and exit pallet 32a. It ends by the fork 33a working with the ellipsis 44a from the oscillator 4a.
Geometrically, in this configuration, the escapements must be identical by a mirror reflection. The functions of the swiss lever escapement is well known and will not be further described here.
The oscillators 4a, 4b are necessarily identical, and are assembled in head-to-toe configuration. Their components (collet 44a,b and spiral 45a,b) are also geometrically identical and assembled the same way. When observed along the cage axis 5 they appear to be identical according to a planar symmetry. Their motions are most of the time synchronous and opposite from each other. The rest of the time, they exist in a wide range of transient behaviors during which the frequencies are in the process of balancing each other out—i.e. the motions are not completely synchronous.
In order to balance the cage, the axes of the two escapement mobiles 2a, 2b are parallel to the cage axis ZC and placed in diametral opposition relatively to that axis. So are the axes of the two levers 3a, 3b. This placement can be seen in
The escapement mobiles 2a,b are made of the escapement pinions 20a,b and escapement wheels 21a,b. Each pinion 20a,b rotates around a compensation wheel 50a,b. In order to keep the system functioning during asynchronous periods, the two compensation wheels are linked to the differential via transmission mobiles.
The representation is limited to the bridgeworks on the double cage 1a, 1b, the escapements (escapement mobiles 2a,b, levers 3a,b), the oscillators 4a,b. The cage 1 is set in motion by the cage belt gearing 101.
The fixed elements of the cage 1 are a cage wheel 10, shared by the two half-cages 1a, 1b as their base. The escapement plates 11a,b carry the levers 3a,b and the escapement mobiles 2a,b. The lever 3a,b is positioned by the lever bridge 12a,b, which also holds the oscillators 4a,b. The escapement bridge 13a,b holds the escapement mobiles 2a,b.
The cage 1 is held in position by it's pivots 14a,b (
The layered organization of the cage 1 is highlighted in the sideview in
The differential 5, shown in
The frame 52 carries the input pinion 54 that is led by the wheel 56, itself linked to the horological mechanism MH.
The output mobiles 53a,b are each made of a tubular pinion 531, and an output wheel 532 pressed on the pinion.
The satellites 55 are assembled in pairs, positioned head-to-toe, and the pairs are installed in the frame 52 in diametral opposition relatively to the axis ZD.
The four satellites 55 are identical.
According to the references in
According the
The axis of the satellites must be located on a cylinder whose central axis is ZD so that the long pinions 551a,b mesh with their respective output pinions 531a,b. Also each long pinion 551 has to mesh with the output pinion 531, and the output pinion 531 must not interact with the short pinion 552. The short pinion must therefore stay over/under the output pinion 531 as shown in
The possibilities of meshing two gearings at a time between 531, 551, 552, is made possible by the asymmetry in the satellite pinion sizes.
The axes 553a,b of the satellites 55a,b are diametrically opposite relatively to ZD, on a circle centered on this axis. The minimum diameter at the waist of the differential D is defined by this circle, thus the grooves 525 in the frame 52 are deep enough that the frame diameter at this point does not exceed the circle.
The diametrically opposite configuration of the satellite pairs and the transverse orientation of the frame 52 create a cross pattern that is balanced around the axis ZD. This cross disposition is shown in
The
The output mobiles 53a,b have a speed of ω1=(ω+δω) and ω2=(ω−δω) around the axis ZD. These speeds are respectively superior and inferior than the average speed ω=(ω1+ω2)/2 according to the function of a differential.
To conclude and sum it up, one needs to notice that the structure of the differential of the realization in
In this mode of realization the frame 52 passes through the output mobiles 53a,b along the axis ZD, and receives the input pinion 54 over one of the two output mobiles.
Going back to the full view in
The differential functions with flat gearing and comprises:
The satellites 55a,b (STa,b) are used as inverting links for the two output mobiles 53a,b (Sa,b). The inverters operate in pairs to cancel the resulting pressure on the gearing. The four satellites 55 (STa, STb, ST′a, ST′b) have the same number of teeth. The rotation axes of the satellites 55 (STa,b) are parallel to the rotation axis ZD of the differential 5(D) frame 52 (CH). The axes of the satellite 55 (STa,b) pairs are set in diametral opposition relatively to the axis ZD.
The satellites 55a,b (STa,b) mesh simultaneously with their output mobiles 53a,b (Sa,b). As a consequence of the equal number of teeth, the two output pinions 532a,b (Sa,b) rotate at the same speeds in opposite directions, when considered in the differential frame referential.
Following the same reasoning, in a referential that is exterior to the differential, the rotation speed of the differential frame 52 (CH) is equal to the averaged speed between the two output pinions 532a,b (Sa,b) rotation speeds.
This layered differential 5 (D), uses flat gearings 53a,b, 55a,b (Pa,b, STa,b, 5a,b) to replicate the behavior of a conical gearing differential. Although more complex by having more elements, this configuration allows the usage of flat gearing norms (NIHS 20-25 for example) instead of less efficient and more complicated to machine conical gearing. Moreover the pivoting is more efficient due to having a rotation between two pivots.
The two output pinions 531 of the differential 5 are attached to the output wheels 532 (Sa,b), meshing with the transmission mobiles 51a,b (ERFa,b), themselves meshing with the compensation wheels.
In this likening of the
In a traditional tourbillon configuration, the fixed wheel is used as a circle on which the escape pinion rolls, which then transforms the cage rotation into a satellite motion around the fixed wheel.
In the configuration described according to the invention, the cage 1 (CC) itself was slowed down and the remainder of the necessary motion was brought by the compensation wheel 50 (RF), thus replacing the fixed wheel. As a consequence, the compensated wheel is always pressing against the escapement pinion 20 (ME), which allows the introduction of a differential 5 (D) to take into account the discrepancies in regulation between the two compensated wheels 50a,b (RFa,b).
The differential 5 (D) is set in motion by the rest of the movement (not shown) through it's input pinion 54 (ED) and it's frame 52 (CH).
In order to simplify the presentation of the claims, every similar references are not systematically retranscripted in the claims. They only are when it is necessary for the understanding.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20-01889 | Feb 2020 | FR | national |
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| WO-2018083586 | May 2018 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20210263472 A1 | Aug 2021 | US |
