EP2701013B1 - Clock movement with extended power reserve - Google Patents

Description

Technical field of the invention

The present invention relates to a watch movement with extended power reserve, for example mounted in a mechanical watch. In particular, the invention aims to equip mechanical watches, for example wristwatches, chronographs and other watches, automatic or manual winding, preferably of high standing, a system that allows to double or even to further extend the duration of the power reserve.

State of the art

In mechanical watches, the energy source for driving the wheel and the hands, including the date display, is a spiral spring wound in a barrel.

When a mechanical watch is not reassembled regularly, or a self-winding watch is not worn for several hours, the watch spring relaxes completely, and the watch stops. This is all the more unpleasant because not only the display of the time stops but also the indication of the date by the wheel or the wheels of the calendar. The average power reserve of a normal watch whose spring is completely stretched, that is to say which is well raised, is about 40 to 60 hours.

There are many reasons for a watch to discharge its energy until it stops. The main reasons are on the one hand the non use of it (chest, weekend ...) or more simply forgetting reassembly of it for non-automatic watches. It is therefore highly desirable to have watches with a greater power reserve than known watches.

In the past, this defect has already been recognized in mechanical watches, and attempts have been made to remedy this problem. For example, the patent Swiss No. CH-693 155 mentions the goal of increasing the power reserve of a watch movement by reducing as much as possible the loss of engine torque during the first 24 or 48 hours of operation. This goal would be achieved by providing two barrels of equal characteristics alternately driving the watch movement and working alternately with a blocking switch between the two barrels.

European patent application no. EP 11188982.0 ( 2'455'820 ) proposes the use of a motor member comprising a barrel in which are mounted two superposed and coaxial springs.

These two documents quoted above are only examples for watches with two barrels or two springs because there are many publications of these proposals.

Such proposals to solve the problem of the increase of market are not very interesting because these solutions schematically propose to put as much barrel, allowing the storage of the energy, that of desired power reserve. The power reserve is therefore increased despite the space available.

Moreover, the state of the art remains silent concerning an examination of the torque distribution in a watch movement, namely that we have not yet tried to find out where the different energy demands are in the movement. On the other hand, the proprietor posed as an object the analysis of the couple, from the barrel to the needles.

The document U.S. 3,177,975 A is interested in a problem encountered in mechanical timers. This problem is that the movement of the gear slows down during the countdown of time. To remedy this problem, the document U.S. 3,177,975 A proposes a solution in which the elastic elastic element is initially wound around a rotary cam, so as to unfold from this cam during the countdown of time.

In the document EP-1 914 604 A1 it is a watch movement designed for the purpose of transmitting energy between the energy source and the oscillator at constant torque. In the solution proposed to achieve this goal, a cam of variable radius is introduced into the kinematic chain carrying the energy transmission.

Summary of the invention

The main object of the invention is a watch movement for a mechanical watch whose reserve is considerably extended. In addition, the invention relates to a mechanical watch incorporating such a movement.

The invention further aims to allow the user of the watch to manually change the operating state between normal operation and operation with the extended reserve. It is also envisaged that the current state (normal reserve - extended reserve) is indicated by the watch. In addition, the extended reserve operating mode must not disturb the time base.

The present invention makes it possible to attain the objects targeted; the extended power reserve movement is defined in claim 1. The definition of the mechanical watch is in claim 14.

The chronometric performances of a watch are improved when the oscillator stores a lot of energy: this makes it less sensitive to disturbances. When the watch is not worn, we can consider lowering the energy supplied to the balance in favor of the power reserve.

The licensee first undertook extensive research to determine the distribution of couples in a watch movement. The various components of the gear train as well as the drive of the time and date display device have been scrutinized in detail to determine the locations of maximum energy consumption. It has been found that, apart from the date gear, the pendulum requires the most energy. This is conceived because the rocker must be accelerated from a stop position and against the force of a spiral spring, then it must be stopped (when the force applied is neutralized by the force of the spring), and then it returns to its position. initial position where it will be stopped again to operate the exhaust.

The decrease in the energy demand of a watch movement is obtained, according to the invention, by a decrease in the oscillation angle (amplitude) of the balance. This reduction can be obtained, according to a particular embodiment of the invention, by changing the speed ratio at the center barrel gear. Increasing this ratio decreases the torque on the wheel of the exhaust, and the amplitude of the balance is lowered in favor of the power reserve.

Another possibility to extend the power reserve of the watch, for the moment not preferred, would be a modification of the watch spring a part of which is used during normal operation, and another separate part remaining triggered is engaged when the state "rest" is activated.

The respective and reversible changes in gear ratio between the barrel and the center wheel (the center) can be achieved in several ways. They will be described in the special description of the invention in connection with the figures.

When changing the gear ratio in the gear train in operation, however, it is important to avoid a disturbance of the display and to ensure compatibility with the existing functions of the watch. The torque drop is then limited by the minimum torque necessary to cause a complication, for example the operation of the display of the calendar and to overcome a spring. In addition, in normal operating mode, do not alter the chronometric aspect.

The licensee also found that the decrease in torque transmitted to the pendulum has no influence on the running of the calendar. The dates are always correctly indicated. This property of the system according to the invention eliminates a serious disadvantage of known watches in which, after stopping the watch following the exhaustion of the reserve, the display of the date does not follow and must be updated which is a long and painful operation.

On the other hand, the work of the exhaust with a low amplitude pendulum could follow a certain delay of the minute hands, but the setting of the time setting is fast and easy.

Brief description of the drawings

• la fig. 1 est un diagramme montrant le couple et l'amplitude du balancier par rapport aux heures de marche d'un mouvement d'horlogerie ;
• la fig. 2A montre le principe d'un mode de fonctionnement normal d'un mouvement d'horlogerie autour du barillet ;
• la fig. 2B montre le principe d'un mode de fonctionnement à couple de sortie diminué du mouvement d'horlogerie de la fig. 2A ;
• la fig. 3 montre un autre principe de changement entre un mode de fonctionnement normal et un mode de fonctionnement à couple de sortie baissé ;
• la fig. 4A montre un troisième principe d'un mode de fonctionnement normal d'un mouvement d'horlogerie autour du barillet ;
• la fig. 4B montre le principe d'un mode de fonctionnement à couple de sortie diminué du mouvement d'horlogerie de la fig. 4A ;
• la fig. 5A montre schématiquement une première réalisation pratique du dispositif selon la fig. 4A ;
• la fig. 5B montre schématiquement une première réalisation pratique du dispositif selon la fig. 4B ;
• la fig. 6A montre schématiquement une deuxième réalisation pratique du dispositif selon la fig. 4A ;
• les fig. 6AA et 6AB indiquent des détails du comportement de l'engrenage ;
• la fig. 6B montre schématiquement une deuxième réalisation pratique du dispositif selon la fig. 4B ; et
• la fig. 7 est une représentation schématique d'une réalisation pratique de la commutation entre le mode normal et le mode baissé selon les fig. 4A et 4B.

The invention will be better explained with the aid of the description of particular or preferred embodiments, with reference to the appended drawing in which:

• the Fig. 1 is a diagram showing the torque and amplitude of the pendulum relative to the running hours of a watch movement;
• the Fig. 2A shows the principle of a normal mode of operation of a clockwork movement around the barrel;
• the Fig. 2B shows the principle of a mode of operation with reduced output torque of the watch movement of the Fig. 2A ;
• the Fig. 3 shows another principle of change between a normal mode of operation and a mode of operation with a lowered output torque;
• the Fig. 4A shows a third principle of a normal mode of operation of a clockwork movement around the barrel;
• the Fig. 4B shows the principle of a mode of operation with reduced output torque of the watch movement of the Fig. 4A ;
• the Fig. 5A schematically shows a first practical realization of the device according to the Fig. 4A ;
• the Fig. 5B schematically shows a first practical realization of the device according to the Fig. 4B ;
• the Fig. 6A schematically shows a second practical embodiment of the device according to the Fig. 4A ;
• the Fig. 6AA and 6AB indicate details of the gear's behavior;
• the Fig. 6B schematically shows a second practical embodiment of the device according to the Fig. 4B ; and
• the Fig. 7 is a schematic representation of a practical realization of the switching between the normal mode and the lowered mode according to the Fig. 4A and 4B .

Detailed description of the invention

The Fig. 1 is a diagram that shows the relationship between the torque in g · mm on the wheel of medium, provided by the barrel, and the running hours of the watch movement after a winding of the watch spring. The ordinate of the diagram also shows the angle of oscillation of the balance in degrees.

The necessary measures were undertaken by the licensee on one of its calibres.

During normal operation, the torque supplied is then 112 g · mm (CPL ini curve) and the amplitude of the balance is 240 ° (curve A ini); the watch stops after 90 hours of walking. When an increased speed ratio is introduced between the barrel and the medium wheel (GM), for example with a multiplication of 1.5 times, the torque then falls to 75 g · mm and the amplitude of the pendulum to 205 ° ; the march already lasts 135 hours. These conditions are represented by the curves CPL 1,5 (for the torque) and A 1,5 (for the amplitude of oscillation of the clockwork movement).

Finally, applying a multiplication of 2.5 times, we measure an initial torque of 45 g · mm and an amplitude of the balance of 165 °. The movement then has a power reserve of approximately 225 hours measured until the total stop of the movement but a usable reserve of 200 hours, see the curves CPL 2,5 for the torque and A 2,5 for the amplitude of the balance.

An extensive analysis of the conditions of this test gives the following indications: The torque needed to drive a perpetual calendar (QP) is 3.05 g · mm. However, for all the configurations envisaged, the available torque for the entire power reserve is greater than 10 g · mm.

For configurations with a multiplier ratio, it is necessary to take into account the performance of the mechanism. Based on a yield of 40%, which is more than pessimistic (we measured and calculated yields around 80%), we still have enough torque for QP training.

Considering a possible delay of the watch movement during the total course, it was found that a change in the amplitude of the pendulum from 250 ° to 120 ° would have a daily delay of about 20 sec, and a passage from 180 ° to 85 ° generates a delay of the order of 26 sec.

Torque measurements were made using a Variocouple instrument from CSA Instruments S.A., Peseux, Switzerland.

Thus, if the proposed mechanism carries the power reserve of a watch to a week or more, it would result in a delay of a few minutes at most. The user would find his watch in working order, calendar indications up to date, and only have to make a correction of the hour of a few minutes, a much simpler procedure than updating a QP.

In what follows, three embodiments are presented for the construction of a watch movement according to the invention. In these three modes of implementation, it is a question of a change in the speed ratio between the cylinder and the center wheel.

The Fig. 2A first shows the principle of the normal mode of a classic gear of a watch movement. Ratchet 10 is distinguished with its shaft 19 which passes through the cylinder 12. The output shaft 14 of the cylinder supports a satellite 17 of a planetary gear train 20 composed of a ring gear 11, a central gear (sun gear) 18 and several satellites 17 of which only one is shown. In this configuration, the shaft of the central gear is fixed relative to the movement by the attachment 15, and the output 16 of the gear is constituted by the ring 11.

The low power mode is represented at the Fig. 2B . The pieces are the same as those of the Fig. 2A , and their reference signs are increased by 100; for example, ratchet 10 at the Fig. 2A is the ratchet 110 at the Fig. 2B . On the other hand, in this configuration, the ring 120 is blocked by the attachment 115, and the satellite 117 transmits its force directly to the central wheel 118 whose shaft forms the output 116. This rather simple change in the operation of FIG. the gear a reduction in the ratio between the barrel and the wheel of great average between 1.25 and 5 according to the number of teeth of the meshing wheels. This change of ratio has the effect of multiplying the output speed, thus a decrease in the torque transmitted to the balance.

However, a disadvantage of this embodiment of low power mode operation is that the output of the sun gear is different depending on the mode of operation. Of course, a technical solution to bring the output of the train on the same axis is available but it increases the number of parts and therefore the cost and the size of the device.

A second main mode for changing the torque provided by the watch spring is shown in FIG. fig.3 . The barrel 30 carries two wheels, a relatively small wheel 32 on its upper face, and a relatively large wheel 34 on its lower surface, the planes of the two wheels being parallel. The wheels 32 and 34 can mesh alternately in two center wheels 36 or 40, respectively, which are both fixed on a common shaft 38 and whose vertical spacing is a little larger than the vertical distance of the two gears. 32 and 34 of the barrel. This shaft 38 can be moved vertically according to the arrow 42.

In the normal mode, the small wheel 32 is engaged with the large center wheel 36. When the movable assembly 36, 38, 40 is raised according to the arrow 42, the large center wheel 36 comes out of engagement, and the small Center wheel 40 meshes with large barrel wheel 34. Of course, the multiplication ratio 32/36 then becomes a 34/40 multiplication ratio which is higher and has the effect of longer duration of the power reserve. .

The Fig. 3 is only schematic. Any other relationship between the four wheels concerned will be possible.

The Fig. 4A and 4B show a third main embodiment for changing the torque provided by the watch spring. The gears in play are reproduced quite schematically.

We first refer to the Fig. 4A . A barrel 52 has on its upper part a toothing 50 which is able to transmit a movement via the wheel 61 which is integral with an axis 62, the center mobile (not shown). A planet gear consisting of a ring gear 54, satellites 56 (only one of which is shown) and a sun gear 58 is inserted between the cylinder 52 and the toothing 50.

In the arrangement of the Fig. 4A which represents the operation in normal mode, the toothing 50 of the barrel and the sun gear 58 are integral, the ring 54 of the cylinder is secured to the cylinder 52, and the satellite 56 pivots on an axis 64 secured to the cylinder 52. In this configuration, when the barrel is unwound, the satellite 56 can not rotate around its axis of rotation. Therefore, everything happens as if the elements 54, 56 and 58 were integral, and they all rotate at the same speed as the barrel 52. The planetary gear is then completely transparent. The toothing 50 of the barrel 52 thus rotates also at the same speed as that of the barrel.

The Fig. 4B shows a scheme of operation in low power mode and is based on the Fig. 4A . The ring 54 is blocked which is symbolized by the stud 55. In this configuration, the ring 54 of the barrel 52 is no longer secured to the barrel 52 but fixed (to a bridge or plate). When the barrel unwinds, it forces the satellite 56 to roll on the ring of the barrel 54. In its movement, the satellite 56 will rotate the sun gear 58 at a higher rotational speed than the barrel 52, according to the size of the planetary gear. The multiplier speed ratio of the sun gear will therefore increase the power reserve and reduce by the same torque transmitted to the center mobile.

The Fig. 5A and 5B illustrate a practical embodiment of the third main mode for changing the torque provided by the watch spring. The gears in play are represented only schematically.

It is first referred to the Fig. 5A which shows the operation of the watch movement in normal mode. Certain elements, familiar to the person skilled in the art, are not represented, such as the cylinder 52 (see Fig. 4 ) and its teeth 50.

The ring of the cylinder 54 has a triangular toothing on its largest diameter. This toothing will work with the pawls 68. The axes of rotation of the pawls 68 and satellites 56 are integral with the barrel.

The ring of the barrel 54 is pivotally connected relative to the barrel. The center mobile, not shown, performs a turn in one hour. For the understanding of the following explanations, we will consider it as immobile.

In this configuration, when the barrel is unwound (it is free), according to the direction of rotation indicated by the arrow, it forces the satellites to roll on the sun gear 58 which is stationary since it is engaged with the center wheel by through the teeth of the cylinder 50, see the Fig. 4A . The satellites 56 mesh with the barrel ring 54: by sizing the planetary gear, the rotational speed of the ring 54 will be greater than that of the barrel 52. As a result, the triangular teeth of the ring 54 will block in one end of a pawl 68.

From this state, the pawls 68, the ring of the cylinder 54 and the satellites 56 are stationary relative to the cylinder 52. The planetary gear becomes transparent, the ring 54 also rotates at the same angular speed as the cylinder 52.

It should also be noted that the locking time of the ring 54 on the barrel via the pawls is very small: it corresponds to a relative displacement of the ring relative to the barrel by one third of the angular pitch of the toothing triangular.

Now reference is made to Fig. 5B which shows the operation in low power supply mode.

In this configuration, the control finger 72 immobilizes the ring 54 of the barrel 52. When the barrel is unwound, it forces the satellites 56 to roll on the ring 54 of the barrel. In this movement, the satellite 56 will rotate the sun gear 58 at a higher rotational speed than the barrel 52 (according to the sizing of the planetary gear). The pawls 68 oscillate slightly on the triangular teeth of the ring 54 and have no function.

The Fig. 5A and 5B represent 3 satellites: only 1 or 2 are needed.

This embodiment is less cumbersome than the first embodiment. The external triangular teeth of the barrel ring thus cooperate with two distinct elements: the control finger 72 to immobilize it, and the pawls 68 to make the ring 54 integral with the barrel 52.

The Fig. 6A, 6AA, 6AB and 6B show a second practical embodiment of the third embodiment of the invention which is based on the Fig. 4A and 4B .

We first refer to the Fig. 6A which illustrates the normal mode of operation of the watch movement. The gearing includes a barrel ring 54, a planet gear 56, a sun gear 58, a control finger 66 and a barrel 52. In addition, there is provided a one-way gear 74 which is engaged with the sun gear 58.

The ring of the barrel 54 is pivotally connected relative to the barrel 52, as in the embodiment according to the Fig. 5A and 5B . The axes of the satellite 56 and the unidirectional pinion 74 are integral with the cylinder 52. The sun gear 58 can be considered as immobile to simplify the understanding of the mechanism.

When the barrel is unwound, it forces the unidirectional pinion 74 to roll on the sun gear 58. The geometry of this pinion tolerates only one direction of rotation of the gear; these conditions are summarily represented to Fig. 6AA and 6AB . We see on the Fig. 6AA that the sun gear 58 rotates clockwise, according to the arrow X, and is blocked by the toothing of the unidirectional pinion 74. In this configuration, there is a blocking direction: from this state, the unidirectional pinion 74, the ring 54 and the satellite 56 are stationary relative to the cylinder 52. The planetary gear becomes transparent, and the ring 54 also rotates at the same angular speed as the cylinder 52.

On the other hand, Fig. 6AB shows that the sun gear 58 turns the other way with respect to the Fig. 6AA , and in this configuration, a rotation of the sun gear is possible because the unidirectional pinion 74 can be driven, and this rotation is transmitted via the satellite 56 to the ring 54 which then turns slower than the cylinder 52.

The Fig. 6B shows the operation of the watch movement in low power mode. The control finger 66 immobilizes the barrel ring 54. In unwinding, the barrel 52 forces the satellite 56 to roll on the ring of the barrel 54. In this movement, the satellite 56 will rotate the sun gear 58 at a speed of rotation greater than that of the barrel 52 (according to the sizing of the planetary gear).

The unidirectional pinion 74 rotates in a vacuum and has no function. He is trained but without effect.

This configuration has the advantage over the first embodiment ( Fig. 5A and 5B ) that this solution requires fewer components, and that all functions to switch from one mode to another are realized in the plane of the planetary gear. In the case of Figure 5B the finger 6 passes over the pawl 66 and requires two levels. The present solution therefore has fewer components and is less cumbersome.

Another practical embodiment of switching between the normal mode and the low power mode according to the Fig. 4A and 4B is represented at the Fig. 7 . On a plate or bridge 82 is pivotably mounted a double switching tooth 80, secured to the pawl 15A, 115A. The pawl is loaded by a leaf spring 88 which holds it in the chosen position. The pawl includes an index 90, visible from the outside, which indicates the position of the chosen pawl, or normal walking ("NORMAL") or walking with extended reserve ("EXTENDED"). This position can be brought to the terminal stop conditions by a lever 86, accessible from outside the watch, guided in translation on the plate 82. The finger 87, guided in rotation by the lever 86, cooperates with the plans 80A and 80B of the switching element 80 to effect the change of state. The rotation of the finger 87 is limited by a frame 84 fixed to the plate 82.

As is apparent from what follows, the invention provides a simple but effective system for substantially extending the running of a mechanical watch. The invention can be applied in particular to simple mechanical watches but also to complicated watches, with calendar indications, chronograph, chronometers, etc.

This very thin, visible and recognizable system, which can be integrated into any of the mentioned watch products, makes it possible to control the power reserve in short or long duration, and the watch can for example pass the weekends without visible degradation, the calendar not changing not during all this rest. The user has the choice of the desired mode and is informed by the watch of the selected mode. This change between normal mode and extended power reserve mode can be manual or automatic.

Following the description above, it is necessary to add some further considerations.

Indeed, when dimensioning a cylinder spring, compromises are sometimes necessary between the characteristics of the spring (size, torque variation, number of winding turns) and the value of the power reserve. The licensee has demonstrated that it is possible, with this device, to significantly increase the value of this power reserve: this criterion is no longer a constraint to be considered when sizing the mainspring. The latter can be optimized to achieve the desired performance of the movement.

The invention is not limited to the embodiments of a watch movement with a long power reserve described above and shown in the figures. Once the principles of the invention have been appreciated, those skilled in the art will be able to find a suitable embodiment. Such an approach does not constitute an exit from the field of protection conferred by the present patent whose application is limited only by the content of the claims.

Claims (14)

1. Mechanical timepiece movement, comprising an energy source able to provide energy via a gear train to an oscillator comprising a balance as regulating organ, characterized in that the timepiece movement comprises switching organs able to switch between two modes of operation, in one of which the ratio of the gearing between the energy source and a wheel of the gear train is different from the other mode of operation, these switching organs enabling a reduction of the torque provided to the oscillator for the benefit of the power reserve.
2. Timepiece movement according to claim 1, characterized in that the energy source is a spiral spring.
3. Timepiece movement according to claim 1 or 2, characterized in that it comprises a barrel (30; 52) able to transmit the energy of the energy source via the gear train to the oscillator, the switching organs being organs for switching between two modes of operation, in one of which the ratio of the gearing between the barrel and a wheel of the gear train is changed with respect to the other mode of operation.
4. Timepiece movement according to claims 2 and 3, characterized in that the spiral spring is accommodated in the barrel (30; 52).
5. Timepiece movement according to claim 3 or 4, characterized in that it comprises a planetary gear train (54, 56, 58) between the barrel (52) and the gear train, the rate of reduction of the gearing being able to be changed, to reduce the torque provided, by blocking one or the other of its sun gear and ring gear in order to change the torque provided by the barrel.
6. Timepiece movement according to claim 3 or 4, characterized in that the barrel (30) bears on its two parallel faces two wheels (32, 34) of different diameter, and that two parallel follower wheels (36, 40), having a diameter adapted to the one or the other of the barrel wheels, being able to engage themselves selectively in the one or the other of the barrel wheels, are disposed in parallel in order to obtain the supply of two levels of torque generated by the barrel.
7. Timepiece movement according to claim 3 or 4, characterized in that it comprises a planetary gear train (54, 56, 58) following the barrel (52) the toothing of which is fixed with respect to the sun gear (58), the ring gear (54) of the barrel (52) is fixed with respect to the barrel (52), and the planet gear (56) is able to pivot on a shaft fixed with respect to the barrel, and that, in the mode of operation of low energy feed, the ring gear (54) is no longer attached to the barrel, but is fixed to a fixed point of movement, rendering the ring gear immobile.
8. Timepiece movement according to claim 7, characterized in that the ring gear (54) of the barrel (52) has a triangular outer toothing able to work with one or more pawls (68), the shafts of rotation of the pawl or pawls (68) as well as of the planet gears (56) being fixed with respect to the barrel (52), and that, in the mode of operation of low energy feed, a control finger (66, 72) is disposed in such a way that it is able to immobilize the ring gear of the barrel.
9. Timepiece movement according to claim 7, characterized in that the planetary gear train further comprises a unidirectional pinion (74) engaged with the sun gear (58), but not engaged with the inner toothing of the ring gear (54), the shaft of rotation of the planet gear (56) and of the unidirectional pinion (74) being fixed with respect to the barrel (52), and that, in the low energy feed mode of operation, a control finger (66) working with an outer triangular toothing of the ring gear (54) is inserted in this toothing, the ring gear (54) is immobilized, and the planet gear (56) is able to drive in rotation the sun gear (58) at a higher speed of rotation than that of the barrel (52).
10. Timepiece movement according to one of the preceding claims, characterized in that the device for reducing the torque is designed and dimensioned to carry out a reduction of the torque by a ratio R, having as an effect an increase in the power reserve by the same ratio R.
11. Timepiece movement according to one of the preceding claims, characterized in that the device for changing the torque is accessible from outside a watch having this movement and is able to be manually manipulated.
12. Timepiece movement according to one of the claims 1 to 7, characterized in that the device for changing the torque is designed to be automatically manipulated.
13. Timepiece movement according to one of the preceding claims, characterized in that its state, normal operation and operation in prolonged power reserve, is indicated by a hand or the like, which is visible from outside a watch having this movement.
14. Mechanical watch, comprising a timepiece movement according to one of the claims 1 to 13 for a prolonged power reserve.

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