EP1593005B1 - Calendar mechanism for displaying the day of the week and the day of the month in a timepiece - Google Patents

Abstract

The invention is a timepiece calendar mechanism for displaying the date and the day of the week, including a date indicator in the form of an internally toothed crown. The date indicator is driven by a first drive wheel having an external toothing so as to be able to be driven about an axis of rotation by a wheel set secured to an hour wheel of the timepiece. The toothing includes a prominent tooth, longer than the others, which abuts against a tooth of the inner toothing of the date indicator to move it forward one day in a time interval located around a determined time of the day. The mechanism also includes a day of the week indicator that moves forward one day during the time interval.

Description

TECHNICAL AREA

The subject of the present invention is a calendar mechanism for displaying the date and the day of the week in a timepiece, comprising a date indicator in the form of an internally toothed ring gear, means for driving this date indicator comprising a first drive wheel having an external toothing to be driven about an axis of rotation by a mobile integral with a wheel hours of the timepiece and this toothing comprising a protruding tooth, longer than the others , which comes to rest on a tooth of the internal toothing of the date indicator to advance it by one day in a time interval situated around a given time of the day, this mechanism also comprising an indicator of the day of the week, means for training this weekday indicator to advance it one day during said time interval and means for positioning said indicators.

TECHNOLOGICAL BACKGROUND

A mechanism of this kind, represented by the document CH 684 980G , and similar to that which is part of certain movements of watches already manufactured and marketed by the applicant is represented, seen in exploded perspective at the figure 1 , at the same time as other elements of the movement which have a direct relation with this mechanism.

Among these elements is a clock wheel hours 2 mounted in the center of the movement and making a turn in 12 hours, the barrel 4 is intended to carry a not shown hour hand.

Inside this barrel 4 can rotate a barrel 6 of a minute wheel itself surrounding an axis 8 of a wheel of seconds, this barrel 6 and this axis 8 being provided to respectively carry a minute hand and a second hand also not shown.

On the barrel 4 of the hour wheel 2 and in contact with this wheel is fixed a pinion 10 with six teeth 12, which meshes with a drive wheel 16. This drive wheel which pivots on a fixed shaft 14 of the movement and which has twelve teeth 18, in order to perform a turn in 24 hours, is alone responsible for driving both a disc of the days of the week 20 integral with a star of the days 22 and a date crown 24, a way that will be explained in detail later.

Among the elements of the movement having a direct relationship with the calendar mechanism also includes a plate 26 partially shown which comprises an upper flange 28 provided to support a dial 30 provided with a window 32. This plate 26 which allows axially positioning the dial 30 also serves to position it angularly by means not shown, so that its window 32 is at 3 o'clock to allow the user of the watch containing the movement to read correctly the day of the week and the date of this day through this window.

Furthermore, the plate 26 also serves as a support for the date ring 24 which is surrounded and held in place radially by the rim 28 of this plate.

As shown in the drawing, the day 20 disc which has two abbreviations of the seven days of the week in one language and the day star 22 which consequently comprises fourteen teeth 34 are mounted so as to be pivotable around the mouth. 4 of the hour wheel 2 and held in place axially by a key 36, the assembly of the disc 20 and the star 22 can be done for example by riveting or laser welding.

Regarding the date ring 24, which can be obtained by cutting and folding from a sheet metal or a thin metal strip, it has a stair-shaped profile and comprises three concentric annular parts 38, 40 and 42 whose level is decreasing from outside to inside.

The first annular portion 38 whose contour corresponds to that of the crown carries numbers from 1 to 31 regularly distributed over its surface. The second part 40 which receives the disc of the days 20 has a diameter barely greater than that of this disc so as not to hinder its rotation and the difference in level between this second part and the first is such that the day of the week and the date and date appear substantially in the same plane and close to one another in the window 32 of the dial 30. As for the third portion 42 it has an internal toothing which comprises 31 radial and isosceles-shaped teeth 44 which correspond to the 31 days the longest months.

The calendar mechanism of the movement of the figure 1 also comprises a holding plate 46 interposed between the day disc 20 and the third portion 42 of the date ring 24, which is fixed by means of screws 48 to a fixed part of the movement. This plate 46 has three functions. The first and the second consist in axially holding the drive wheel 16 and the date ring 24 without impairing their mobility. The third function is to serve as spring-jumpers for the date crown 24 and for the star of the days 22. For this the plate 46 is cut and folded so as to form a first elastic tongue 50 which extends below of the plane of the main part of this plate and which ends with a V-shaped end, pointing outwards of the movement to engage between the teeth 44 of the date ring 24 and a second elastic tongue 52 s' extending above the plane of the same plate 46 and which also terminates in a V-shaped end but pointing inwardly to engage between the teeth 34 of the star of the days 22 which are at the both radial and isosceles.

To describe in detail the drive wheel 16 and the operation of the calendar mechanism of the figure 1 we will also refer to the figure 2 which shows the wheel 16 still in perspective but on a larger scale.

This wheel 16 comprises a hub 54 through which it is mounted on the shaft 14 and which is connected by a radius-shaped connection element 56 to a ring 58 which carries the teeth 18 mentioned above.

Among these teeth 18 is a protruding tooth 18 'which extends radially beyond the others so as to be the only one able to engage between the teeth 44 of the date ring 24 while being able to engage the same the others between the teeth 12 of the pinion 10. For a reason that will be understood later this tooth 18 'has a side called "front flank" 60 of the same inclination as the flanks of other teeth that is to say say substantially radial and a "trailing edge" 62 which, at the end of this tooth intended to engage between the teeth 44 of the ring 58 has an oblique face 64 of lower inclination to form an acute angle with the flank before 60.

That said, the wheel 16 also comprises a resilient arm 66 roughly in the shape of an arc of a circle, made of a piece with the other elements of the wheel 16, attached to the hub 54 and extending inside of the ring gear 58. This arm has at its free end a first tongue of substantially rectangular shape and bent at 90 ° in the direction of the front of the movement so as to form a drive finger 68 engageable between the teeth 34 Moreover, the arm 66 and the orientation of the drive finger 68 relative to the flanks of the teeth 34 are provided so that the arm deforms significantly only when it is forced to away from the hub 54 of the wheel 16 and very little in the opposite direction.

Finally, the wheel 16 also comprises a second tongue 70 of substantially rectangular shape, made of a piece with the elastic arm 66, located in the plane of the wheel, at a distance from the end of this arm and extending towards the crown 58. The utility and interest of this second tab which does not interfere in the operation of the calendar mechanism of the figures 1 and 2 will be specified later.

This calendar mechanism of figures 1 and 2 and trailing type that is to say that the advance of the calendar of a unit and the passage from one day of the week to the next are made during a time interval of about four hours around midnight.

As long as the movement is operating normally, outside this range, its engine whether of purely mechanical or electromechanical type drives the pinion 10 clockwise and the calendar drive wheel 16 counter-clockwise indicated by arrow F1 on the drawing. During this period, the wheel 16 meshes neither with the date crown 24 nor with the star of the days 22 whose positions are determined and maintained by the jump springs 50 and 52 so that the date and calendar indications day of the week appear correctly framed in the window of the dial 30 and without shocks to the movement can change these indications.

For a reason that will be explained later the drive wheel 16 is designed so that there is a certain phase shift, for example about half an hour, between the start of training the disc 20 days and that of the date ring 24 or vice versa. Then it is in the first of these situations that we will set ourselves to describe the functioning of the calendar mechanism of figures 1 and 2 and a variant also known from the latter as well as that of the mechanism according to the invention.

Under these conditions, when the drive finger 68 comes into contact with the rear flank of a tooth 34 of the star of days 22 this finger begins to exert on this tooth 34 a couple that opposes the action of the spring -sautoir 52. As the drive wheel 16 rotates in the direction of the arrow F1 the elastic arm 66 is stretched away from the hub 54 and the finger 68 slides along the side of the tooth 34 with which it is in contact and rotates the star 22 and the disc of the days 20 in the direction of the arrow F2. At the same time, the end of the spring-jumper 52 out of the hollow between two teeth of the star 22 in which it was, while the torque exerted by the finger 68 on the tooth 34 increases.

About half an hour after the beginning of the training of the star and the disc of the days, the front flank 60 of the tooth 18 'of the wheel 16 comes into contact with the rear flank of a tooth 44 of the crown of date 24 and then begins to slide on this rear flank and to rotate the date crown in the direction of the arrow F3 that is to say in the same direction as the drive wheel 16 and in the opposite direction to that in which the disc rotates days 20. Meanwhile, the end of the jumper spring 50 begins to out of the hollow between two teeth 18 of the date ring in which it was, this spring begins to stretch and the torque exerted by the tooth 18 'on the tooth 44 with which it is in contact begins to increase.

During the following period, which is the longest of the time interval necessary to change the day and the date, the wheel 16 simultaneously drives the day star 22 and the date ring 24 by providing a torque greater than that the sum of the resistant torques exerted by the jump springs 50 and 52 respectively on the tooth 34 of the day star 22 and that 44 of the date ring 24 with which the tooth 18 'and the tooth 34 of the tooth are in contact with each other; star of days 22, these couples continuing to increase until the end of spring-jumper 52 reaches the top of tooth 34 of the star of days 22.

In a very short instant the spring 52 relaxes when its tip descends into the hollow of the star of the days 22 following that between the teeth of which it was previously, in the direction of the arrow F2. At the same time, the drive finger 68 of the arm 16 is ejected from the toothing of the star of days 22 while it exerted on it a maximum torque and the day of the week indicated by the disk 20 ends move on to the next day.

A little later, the same process occurs for the jumper spring 50, the hollow between the teeth 44 of the date ring 24 between which its end was and the long tooth 18 'of the drive wheel 16 which fact that the indication of the date progresses by one unit.

Thus, thanks to the phase difference between the driving of the disc of the days and that of the crown of the calendar, the total torque supplied by the drive wheel 16 never reaches the sum of the maximum torques exerted by this wheel on the star of days. and the date crown, which makes it possible to prevent a blocking of the drive motor of the movement or at least a return back of this disc and / or this crown.

When a change in the indication of the date in particular during the passage of a month of thirty days or less in the case of the month of February to the following month or a modification of both the indication of the date and the day of the week, for example during a battery change in the case of an electromechanical movement or a prolonged absence of the winding in the case of a mechanical watch, this or these changes can be done manually and quickly by means of a control rod and a correction mechanism not shown on the drawing. In the case of the movements marketed by the plaintiff, as in many others, the control rod is a rod that can be placed in three axial positions, a neutral or reassembled thrust position, a first drawn position in which the display The date can be modified by turning the rod in one direction and that of the day of the week by turning the rod in the other direction and a second drawn position reserved for setting the time of the hands of the watch.

When a date setting occurs outside the time interval where neither the day disc nor the date crown are driven by the wheel 16 this is not a problem. But, very often the date setting and the most frequently the date alone is around midnight that is to say during this interval.

When a modification of the date occurs under these conditions, the mechanism for correcting the date not shown acts on the teeth 44 of the date ring 24 so as to turn the latter in the direction of the arrow F3, against spring-jumper 50 and each time that the leading edge of a tooth 44 comes into contact with the oblique face 64 of the trailing edge 62 of the tooth 18 'of the drive wheel 16, this leading edge of a tooth 44 slides on this oblique face of the tooth 18 'without substantially modifying the angular position of this tooth 18' and this thanks to a clean elasticity of the drive wheel 16 which then deforms very slightly and against the resisting torque then exerted on this wheel 16 by the pinion 10 which rotates in the opposite direction at a much lower speed, which can even be considered as zero.

In the case where, more rarely, the position of the disc of the days must also be modified during the period of time in question, the correction mechanism causes the star of the days 22 in the direction of the arrow F2 by blowing the end of the spring-jumper 52 of a hollow between two teeth 34 to the next. When a leading edge of a tooth of the star of the days 22 comes into contact with the drive finger 68, it forces the elastic arm 66 to curve very slightly towards the hub 54 of the wheel 16 and then to resume its initial position after passing to the top of this tooth 22 by the finger 68.

Moreover, if we change the time in the direction of advance everything happens as when the mechanism is working normally except that if this modification is done while the day and date change process is going on this process is accelerated during the time the time is changed. By cons, if the time change is in the direction of the delay wheel 16 then rotates in the opposite direction to that of the arrow F1. In this case, when the oblique face 64 is or comes into contact with a tooth 44 of the date crown this tooth slides or continues to slide on this face which causes or maintains a slight deformation of the ring of the wheel 16 and so that the position of this wheel remains unchanged. When during the same period the rear face of the tooth 68 comes into contact with a tooth 34 of the star of the days 22 this tooth slides on this rear face, which causes only a slight deformation of the arm 66 in the direction that brings it closer to the hub 54 of the wheel until the tooth 68 reaches the top of the tooth 34. At that time the arm returns to its initial position without the position of the star 22 and the disc 20 days has been changed.

The Figures 3 and 4 illustrate a variant of the calendar mechanism represented on the figures 1 and 2 , which corresponds to a mechanism used in other movements also manufactured and marketed by the plaintiff.

As shown in figure 3 which is a top view of the disc of the days of the week and the star of days, this star always designated by the reference number 22 remains unchanged and still has fourteen teeth 34.

On the other hand, the disc of the days 20 'no longer bears twice the abbreviations of the successive days of the week in the same language, as the disc 20 of the figure 1 , but alternatively the abbreviations of days in two languages, in this case in English and French.

Therefore, to have the day still displayed in the same language, the star and disc of the days should no longer rotate normally one fourteenth of a turn per day but one seventh. For this it is sufficient to bend at 90 ° the second tongue 70 of the drive wheel 16 shown on the figures 1 and 2 to make it a second driving finger 70 ', as shown in FIG. figure 4 . Thus, after the first finger 68 has acted on a tooth 34 of the day star 22 to rotate the day disk 20 'by a fourteenth of a turn, the second finger 70' acts in the same way on the next tooth 34 to rotate the disc again a fourteenth of a turn in the same direction.

As for the first finger 68 and for the same reason, the action of the second finger 70 'is synchronized with that of the tooth 18' so that the total torque that must exercise at the same time the drive wheel 16 on the star of days 22 and the date ring 24 never reaches the sum of the maximum torques necessary to turn this star and this crown.

On the other hand, during a manual change of the day of the week the second finger 70 'acts as the first 68, that is to say that it forces the elastic arm 66 to curve to allow the 'star 22 and the 20 day disc' to switch from displaying the same day from one language to another or from one day to the next in the same language.

Naturally, all that has been said previously about the first drive finger 68 and the arm 66 is also valid for the second drive finger 70 '.

In addition, this variant of Figures 3 and 4 justifies the presence of the tongue 70 in the embodiment of figures 1 and 2 . Indeed, to achieve training wheels 16 used in both cases it is sufficient to cut in a strip or a metal plate flat parts having the two tabs for forming the two drive fingers 68 and 70 'and to bend only one or both of these tongues to obtain wheels that can be used either in the embodiment of figures 1 and 2 or in its variant, which is obviously an economy.

Despite this, this form of execution of figures 1 and 2 and its variant have certain disadvantages.

First, the wheel 16 made in one piece in the same material does not provide an optimization of the training of both the star of day and the crown of date according to the materials of which can be constituted, for example when the date ring is made of copper alloy and beryllium while the star of the day is steel to allow welding on this star a disc of days by laser.

Secondly, for a given movement, the sign and the value of the phase difference between the drive of the day disc and that of the date crown are determined during the design and manufacture of the drive wheel 16. For a variety of reasons, it may be best to start with the date crown instead of the star and disc of the days and not necessarily with the same lead. In the case of known mechanisms Figures 1 to 4 this can only be done by replacing wheel 16 with another.

Finally, thirdly, in these known mechanisms Figures 1 to 4 , the drive wheel 16 which is actually very thin, must cause for a long time both the date crown and the star of days in opposite directions, so that it is then subject to constraints rather large, which may to a large extent limit its life and the proper functioning or even the very operation of the calendar mechanism of which it is part.

SUMMARY OF THE INVENTION

The object of the invention is to provide a calendar mechanism capable of indicating both the date and the day of the week that does not have these disadvantages.

This object is achieved by virtue of the fact that the mechanism according to the invention which corresponds to the definition given in the first paragraph above is remarkable in that the drive means of the indicator of the day of the week comprise a second wheel. with the outer teeth, superimposed and coaxial with the first drive wheel and in that said first and second drive wheels have the same diameter and the same number of teeth and are driven by the same mobile. in solidarity with the hour wheel.

Preferably, said drive wheel is constituted by a pinion fixed on a barrel of said hour wheel and having a number of teeth equal to half that of said first and second drive wheels.

BRIEF DESCRIPTION OF THE DRAWINGS

• les figures 1 à 4 déjà décrites ci-dessus illustrent l'état de la technique qui, à la connaissance de la demanderesse, est le plus proche de l'invention ;
• la figure 5 est une vue en perspective éclatée d'une première forme possible d'exécution d'un mécanisme selon l'invention ;
• la figure 6 est une vue également en perspective éclatée d'une deuxième forme possible d'exécution du mécanisme selon l'invention ; et
• les figures 7 et 8 sont des vues en plan et de dessus de deux roues d'entraînement du mécanisme de la figure 6.

Other features and advantages of this mechanism will appear on reading the following description of two possible embodiments, a description which refers to the appended drawings in which:

• the Figures 1 to 4 already described above illustrate the state of the art which, to the knowledge of the applicant, is closest to the invention;
• the figure 5 is an exploded perspective view of a first possible form of execution of a mechanism according to the invention;
• the figure 6 is also an exploded perspective view of a second possible embodiment of the mechanism according to the invention; and
• the Figures 7 and 8 are plan and top views of two driving wheels the mechanism of the figure 6 .

DESCRIPTION OF PREFERRED EMBODIMENTS

Comparing the figures 5 and 6 to the known variant illustrated by the Figures 3 and 4 of the calendar mechanism also known, represented in the figure 1 we see that apart from the training wheel 16 we find on these figures 5 and 6 not only all parts of this mechanism according to this variant but also the elements of the watch movement partially shown having a relationship with it.

It is therefore not necessary to re-describe all those common parts that are designated on the figures 5 and 6 by the same references as in the previous figures.

That said, the embodiment of the mechanism according to the invention shown in the figure 5 is distinguished from the variant in question by the fact that the single drive wheel 16 of this variant is replaced by two superimposed coaxial wheels 76 and 76 ', having the same diameter and the same number of teeth, respectively 78 and 78', in this case twelve teeth, which are both mounted on the same shaft 14 secured to the frame of the movement and driven by the same pinion gear with six teeth integral with the barrel 4 of the hour wheel 2 of this movement.

Naturally, although they are designated by the same reference numbers and there is not only a calendar drive wheel but two superimposed wheels, the height of the shaft 24 and the thickness of the pinion 10 may be greater than those they had in the embodiment and variant known previously described. For the same reason, the exact shape of the plate 46 which keeps these two wheels in place could be slightly modified, at least locally.

Moreover, as represented on the figure 5 , the wheel 76 which is responsible for driving the date ring 24 has, like the wheel 16 of the Figures 1 to 4 , a hub, a spoke and a ring gear not referenced. On the other hand, it no longer includes elastic arms or fingers for training the star 22 and the disc of the days 20, which means that it could be made in another form provided that it continues to present, d on the one hand, a tooth 78 'longer than the others and of the same shape as before to be able to drive the date crown and, on the other hand, a sufficient elasticity to allow a manual modification of the display of this calendar of days. the same way as with the single drive wheel 16.

As regards, the wheel 76 'which is above the date drive wheel and whose role is to drive the star 22 and the disk 20 of the days of the week, it is identical to the wheel 16 of the figure 2 except that it does not have a particular tooth and that its twelve teeth 78 'are identical.

It is therefore not necessary to describe the operation of the calendar mechanism according to the invention shown on the figure 5 . On the other hand it is useful to show that this mechanism or a similar mechanism well achieve the aims sought by the invention indicated above.

Indeed, in such a mechanism, parameters of each of the wheels 76 and 76 ', such as the material of which they are made, the shape of their teeth or their resistance to wear, can be determined separately according to the structural characteristics and methods of making the mobiles that they cause to optimize the operation of the calendar mechanism of which they are part.

On the other hand, the mechanical stresses experienced by the wheels 76 and 76 'which are also very thin and fragile but which each cause only one moving and in one direction are much weaker than those experienced by a single wheel which drives two mobiles rotating in opposite directions.

Moreover and contrary to the known mechanisms of Figures 1 to 4 the training of the star and the disc of the days can no longer have negative influences on the elastic behavior of the ring gear drive of the date ring 24 and vice versa.

Finally, in the case of the embodiment of the mechanism according to the invention of the figure 5 it is easy to mount the wheels 76 and 76 'on the shaft 14 so that the star 22 and the disc 20 days begin to be driven before the date ring 24 or vice versa. By cons, since the pinion 10 integral with the hour wheel 2 has only six teeth and the drive wheels 76 and 76 'twelve teeth it is not possible to increase or decrease the time interval between the moments when this star and this disc of the days on the one hand and this crown of date on the other hand begin to be driven, this interval remaining inevitably the same one as for the known mechanisms of the Figures 1 to 4 . However, in the case of the mechanism according to the invention there is a simple solution to solve this problem. This solution is to multiply to a certain extent the number of teeth of the pinion 10 and the wheels 76 and 76 ', while maintaining a ratio 2: 1 between these wheels and this pinion. As regards the known mechanisms of the Figures 1 to 4 it would also be possible to increase the number of teeth of the pinion 10 and the wheel 16, which is indeed the case in the actual movements already manufactured and marketed by the applicant, but with a single drive wheel of the mechanism of timing this would not solve this problem.

As in that of the figure 5 , in the embodiment shown in figure 6 , the mechanism according to the invention comprises two superimposed coaxial wheels 80 and 80 'having the same diameter and the same number of teeth, respectively 82 and 82', also twelve in number, mounted on the same shaft 14 secured to the frame movement and driven by the same pinion gear with six teeth integral with the hour wheel 2 of this movement.

As is more clearly shown figure 7 , the wheel 80, intended to drive the date ring 24, comprises a hub 84 from which a broad, substantially radial arm 86 extends. From the end of this radial arm 86, in turn, a resiliently deformable arm 88 is substantially shaped. of arc of circle, which extends in the normal direction of rotation of the wheel 80, indicated by the arrow F1, and which surrounds for the most part the hub 84 to be connected from the inside and by a connecting part substantially radial and rigid 90 to a ring 92 which carries the teeth 82 of the wheel.

As the ring gear of the drive wheel 76 of the embodiment of the figure 5 , the crown 92 has a particular prominent tooth 82 "longer than the others to be able to engage between the teeth 44 of the date crown 24 (see figure 6 ) and which has the same orientation and the same shape as the prominent teeth of the drive wheels of the date crowns that have been discussed so far.

On the other hand, in the form of execution of figure 6 this tooth 82 "is no longer attached to the normal tooth 82 which precedes it when the wheel 80 rotates in the direction of arrow F1 but separated from it by a cut 94.

Thus, when the calendar mechanism is operating normally and when the leading edge 96 of the tooth 82 "comes into contact with the rear flank of a tooth 44 of the date ring 24, this ring does not begin to be driven immediately by the tooth. 82 ". Despite the engine torque exerted by the pinion 10 on the drive wheel 80 to rotate in the direction of the arrow F1 and because of a resistant torque of inertia and friction exerted in the opposite direction on this wheel, the tooth 82 "begins to remain immobile, so that the spring formed by the elastic arm 88 is armed until a substantially radial front flank 102 of the connecting portion 90 comes into contact with a corresponding rear flank 104 that presents the radial arm 86 joining the hub 84 to the elastic arm 88. Meanwhile the width of the cut 94 of the wheel increases.

From the moment when the contact between the leading edge 102 of the connecting portion 90 and the trailing edge 104 of the arm 86 is established, the particular tooth 82 "begins to drive the date ring 24 in the same way as the tooth 78 "of the wheel 76 in the embodiment of the figure 5 , until this tooth 82 "crosses the tooth 44 of the date crown with which it was in contact and falls into the next hollow of the teeth of the date crown, which allows the elastic arm 88 to relax .

So, in the case of this form of execution of the figure 6 and as regards the drive of the date crown, the mechanism according to the invention is no longer of the trailing but semi-trailing type or which amounts to the same semi-instantaneous, which means that the change of the date indication is faster than in the execution form of the figure 5 , the time of this change being roughly halved.

However, when a rapid change in the indication of the date occurs in response to a maneuver of a control rod and when a tooth 44 of the date ring 24 comes into contact with the oblique face 100 of the tooth 82 "this tooth 44 of the date ring exerts on the tooth 82" a torque which tends to rotate the first drive wheel 80 in the direction of the arrow F1. However, since the pinion 10 which can then be considered fixed opposes such a rotation, the tooth 44 of the date ring slides on the oblique face 100, which causes only a slight tension of the elastic arm 88 and a small decrease in the width of the cut 94 of the ring 92 and as soon as the tooth 44 passes the top of the tooth 82 "the drive wheel 80 returns to its original shape.

Similarly, when the pinion 10 rotates in the opposite direction to that of the arrows F1 and F3 to allow a time setting of the timepiece in the direction of the delay, and when the oblique face 100 of the tooth 82 " of the wheel 86 which then rotates in the opposite direction to that of the pinion comes into contact with a tooth 44 of the date ring, the torque exerted by the tooth 82 "on this tooth 44 is not sufficient to change the position of the date ring and the elastic arm 88 and the cut 94 of the ring 92 behave in the same manner as before.

As shown in figure 8 , the wheel 80 'for driving the star 22 and the disc 20 of the days of the week comprises a hub 106, a ring 108 bearing the teeth 82' and connected to the hub 106 by a radius 110, a resilient arm 112 substantially shaped a circular arc which surrounds a portion of the hub 106 and which carries two driving fingers 112 and 114 formed and arranged in the same way as the driving fingers 68 and 70 'of the drive wheel 16 shown in FIG. figure 4 and that is part of the variant of the known calendar mechanism of the figure 1 .

Finally, the elastic arm 112 of the drive wheel 80 'shown in FIG. figure 8 also carries a substantially radial bearing pin 118 located in the plane of this wheel which extends towards the crown 108 and which ends with a rounded end 120.

When the wheel 80 'is driven normally in the direction of the arrow F1 and when the drive finger 114 comes into contact with the rear flank of a tooth 34 of the star of days 22 and begins to exert a torque on this the elastic arm 112 is tensioned and moves away from the hub 106 until the end 120 of the finger 118 abuts against the inner edge 122 of the crown 108. Meanwhile, the first driving finger 114 pushes on the tooth of the star of the days by sliding on the front flank of this tooth to its summit and from the moment when the finger 118 comes into contact with the inner edge 122 of the crown the torque exerted by the finger 114 on the tooth 34 is practically maximal. Then, when the finger 114 has crossed the top of the tooth 34 of the star of days 22 it falls back into the hollow of the star 22 following that between the teeth of which it was previously and after the star of days has turned fourteenth of a turn the elastic arm 112 relaxes.

The same thing happens when the second driving finger 116 rotates the star of the day one fourteenth of a turn in the same direction and when the wheel 80 'is driven rapidly always in the same direction to modify the indication. of the day of the week by manual control.

Moreover, it goes without saying that all that has been explained previously about the direct modification or through a time setting remains valid with some obvious adaptations, for the form of execution of Figures 6 to 8 .

Finally, to finish with this form of execution of Figures 6 to 8 , it should also be noted that the finger 118 also serves as a stop for the ring 92 of the drive wheel 80 of the date ring 24 disposed below the drive wheel 80 'of the star 22 and this in order to avoid a possible wedging between these two wheels which are very thin and which can deform while it turns.

That said, it is quite clear that the invention is not limited to the two embodiments that have just been described.

For example, the disc of the days in two languages could be replaced by a disc in one language like that of the figure 1 . In this case the drive wheel of this disc would have more than one drive tooth.

On the other hand, this disc of the days could only wear once the days of the week and the star of days have only seven teeth.

On the other hand, this same disc and this star could make it possible to display the days in three languages.

With regard to the drive gear integral with the barrel of the hour wheel and the drive wheels of the date crown and the disc of the days, their numbers of teeth could be lower or higher respectively to six and twelve, the essential thing being that the ratio 2 between these numbers is preserved.

Of course, these are only examples because many other embodiments or variants can be imagined without departing from the scope of the invention, as defined by the claims.

Claims (12)

1. Calendar mechanism for displaying the date and the day of the week in a timepiece, including a date indicator (24) in the form of an internally toothed crown, means (10, 76; 10, 80) for driving said date indicator including a first drive wheel (76; 80) having an external toothing (78; 82) so as to be able to be driven about an axis of rotation by a wheel set (10) secured to an hour wheel (2) of said timepiece and said toothing including a prominent tooth (78"; 82"), longer than the others, which abuts against a tooth of the inner toothing (44) of the date indicator to move it forward one day in a time interval located around a determined time of the day, said mechanism also including a day of the week indicator (20), means (10, 76', 22; 10, 80', 22) for driving said day of the week indicator to move it forward one day during said time interval and means (50, 52) for positioning said indicators (24, 20) and said mechanism being characterised in that said means for driving the day of the week indicator include a second drive wheel (76'; 80') fitted with an external toothing (78'; 82), superposed and coaxial to the first drive wheel (76; 80) and in that said first and second drive wheels (76, 76'; 80, 80') have the same diameter and the same even number of teeth (78, 78'; 82, 82') and are driven by the same wheel set (10) secured to said hour wheel (2).
2. Calendar mechanism according to claim 1, characterised in that said drive wheel is formed by a pinion (10) secured to a pipe (4) of said hour wheel (2) and including a number of teeth (12) equal to half of that of said first and second drive wheels (76, 76'; 80, 80')
3. Calendar mechanism according to claim 2, characterised in that said day of the week indicator is a disc (20) coaxial to said date indicator (24) and in that said means for driving said disc include a day star-wheel (22) secured to said disc and driven by said second drive wheel (76'; 80').
4. Calendar mechanism according to claim 3, characterised in that said second drive wheel (76'; 80') pivots on a fixed arbour (14) and includes a hub (106) via which it is mounted on said arbour and which is connected to a crown (108) carrying said teeth (78'; 82) and an elastic arm (112) substantially in the shape of an arc of a circle, attached at least indirectly to said hub and partially surrounding the latter, and in that said elastic arm has at its free end a first drive finger (114) substantially perpendicular to the plane of said second wheel which is engaged between the teeth (34) of said day star-wheel (22) to move said day of the week indicator disc (20) forward one day of the week when said calendar mechanism is operating normally.
5. Calendar mechanism according to claim 3, characterised in that the day of the week indicator disc (20) carries alternately abbreviations of the names of the days of the week in two different languages, in that said day star-wheel (22) includes fourteen teeth (34), in that said elastic arm (112) has a second drive finger (116) also substantially perpendicular to the plane of said second drive wheel (76'; 80') and in that said second drive finger (116) is located in relation to the first finger (114) such that said drive fingers act one after the other on two successive teeth (34) of said day star-wheel in order to rotate said day of the week disc twice by a fourteenth of a revolution in the same direction during said time interval located around a determined time of the day.
6. Calendar mechanism according to claim 4, characterised in that said elastic arm (112) also carries a substantially radial support finger (118) located in the plane of said second drive wheel (80) and having one end (120) which abuts against said crown (108) of said second drive wheel (80') when said elastic arm is deformed in the direction of said crown practically at the moment when said deformation is sufficient to allow said first drive finger (114) to move said day of the week indicator disc (20) forward one day, against said positioning means (52).
7. Calendar mechanism according to claim 4, characterised in that said elastic arm (112), said first drive finger (114), said teeth (34) of the day of the week star-wheel (22) and said means (52) for positioning said star-wheel are designed such that said first drive finger slides over one of said teeth (34) without any significant deformation of said elastic arm (112), in the direction of said hub (106) and owing to a natural elastic deformation of said crown (108) so that said day of the week indication is not altered when said pinion (10) rotates in an opposite direction to that which allows it to drive said second drive wheel (76'; 80') and said day star-wheel in their normal rotational directions (F1, respectively, F2).
8. Calendar mechanism according to claim 2, characterised in that said first drive wheel (76) pivots on a fixed arbour (14) and includes a hub via which it is mounted on said arbour and which is connected to a crown carrying said teeth (78) by a radial arm.
9. Calendar mechanism according to claim 8, characterised in that said prominent tooth (78") of the first drive wheel (76) has a substantially radial front flank like the other teeth (78) of said wheel (76) which acts each time on a tooth (44) of said date crown (24) to move forward the date indication one day when the mechanism is operating normally and a back flank which, at the end of said prominent tooth provided for engaging between the teeth (44) of said date crown, has an oblique face of smaller inclination to form an acute angle with said front flank and to allow said first drive wheel (76), which is then elastically deformed, to rotate in the opposite direction to its normal rotational direction (F1) without altering the date indication, when it is driven in the opposite direction by said pinion (10).
10. Calendar mechanism according to claim 2, characterised in that said first drive wheel (80) pivots on a fixed arbour (14) and includes a hub (84) from which extend a wide radial arm (86), an elastically deformable arm (88) substantially in the shape of an arc of a circle, starting from a free end of said arm (86) and extending in the normal rotational direction (F1) of said first drive wheel, said elastically deformable arm surrounding most of said hub (84) to be attached via the interior and a substantially radial and rigid connecting part (90) to a crown (92) which carries said teeth (82); said mechanism being also characterised in that said prominent tooth (82") of the first drive wheel (80) is separated from the tooth (82) that precedes it when said wheel rotates in its normal rotational direction (F1) by a cut (94) of said crown (92); and in that, when said wheel rotates in the normal direction and when said prominent tooth (82") comes into contact with a tooth (44) of said date crown (24) to drive the latter, said prominent tooth starts by remaining still while said elastically deformable arm (88) tightens in the direction which brings it closer to said hub (84) and that the width of said cut (94) increases, until a front flank (102) of said connecting part (90) comes into contact with a back flank (104) of said radial arm (86) and said prominent tooth (82") comes into contact with the tooth (82) which precedes it, after which said prominent tooth drives said date crown to move it forward one day and then allow said drive wheel (80) to return to its original form.
11. Calendar mechanism according to claim 10, characterised in that said prominent tooth (82") of the first drive wheel (80) has a substantially radial front flank (96) like the other teeth (82) to move the date indication forward one day when the mechanism is operating normally and a back flank (98) which, at the end of said prominent tooth provided for engaging between the teeth (44) of said date crown (24), has an oblique face (100) of smaller inclination to form an acute angle with said front flank (96) and in that when said first drive wheel (80) is driven in the opposite direction to its normal rotational direction (F1) and when said oblique face (100) of the prominent tooth (82") comes into contact with a tooth (44) of the date crown (24), this tooth (44) slides over said oblique face which causes a slight tension in the elastic arm (88) and a slight decrease in the width of said cut (94) of the crown (92) of said first drive wheel (80) but without altering the date indication.
12. Calendar mechanism according to claim 1, characterised in that, when the mechanism is operating normally, the driving of the date indicator (24) is phase shifted in time with respect to that of the day of the week indicator (20), so that the torques necessary for driving said indicators do not reach their maximum values practically at the same time and prevent any malfunction of the timepiece of which they form part.

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