EP0135823B1 - Perpetual calender comprising a quadrennial cycle indicator - Google Patents

Abstract

The perpetual calendar mechanism of the invention comprises in addition to the months indicator a four year cycle indicator which displays successively the normal years and the leap-year. The four year cycle indicator is controlled directly or indirectly by a rotatable assembly journalled on the month star such assembly including a year cam and a Maltese cross enabling it to effect one revolution every four years. In one variant illustrated the mechanism includes a first ring bearing the year indications and a second ring concentric to the first ring bearing an index marker. At each year change the index marker is shifted a quarter turn relative to the indications borne by the first ring.

Description

The invention relates to a perpetual calendar mechanism for a timepiece comprising a month star performing one revolution per year, a month cam fixed on the month star and having solid parts corresponding to the months of thirty-one. days, shallow notches corresponding to those of thirty days and an opening located between the solid parts corresponding to the months of January and March, a mobile pivoting on the star of the months and comprising inter alia a cam of the years arranged to perform a in four years, said year cam having four flanks appearing in turn in said opening, a month indicator and a four year cycle indicator.

In large complication watches, two main types of perpetual calendar mechanism are known. The first of these mechanisms is usually recognized by the small dial on which the month hand moves, which bears the names of the months for four years. The hand responsible for indicating the month then turns in four years. This system therefore makes it possible first of all to recognize that we are dealing with a perpetual calendar, then to immediately know which year the watch is set against the leap year. The second mechanism meets the generic definition given in the paragraph above where the month indicator or hand makes one revolution per year. In this case, however, nothing will indicate that we are dealing with a watch fitted with a perpetual calendar - no more than we will be assured that the watch is correctly adjusted in relation to the leap year if it is not not equipped with an additional four-year cycle indicator.

Such an additional indicator is proposed for example on the movement which bears the number 861389 of the manufacturer Patek-Philippe. In this construction, the star of the months, which carries the hand of the months and makes a turn in one year, controls a train of reduction gears which finally drives a hand of the years which makes a revolution in four years and whose axis is coaxial with the axis of the month hand. It will be understood, however, that this return system is complicated and above all that it takes up space in thickness.

We saw above that in this second kind of mechanism, the star of the months is provided with a mobile which pivots on it and which comprises a cam of the years which is arranged to carry out a turn in four years. The present invention precisely takes advantage of this arrangement and causes the indication of the cycle of four years to depend, not on the rotation of the star of the months but on the position of the cam of the years, which leads to a simplified construction and less cumbersome.

We cited in the research report US-A-527386 which proposes a cam for years making a turn in four years and on the axis of which there is a pointer indicating the cycle of four years. In this patent, however, the years cam is not pivotally mounted on the month star but on a fixed plate serving as a dial for the timepiece. There is therefore no difficulty in providing the cam with an indicator since this cam does not change place with respect to the dial throughout an annual revolution of the month star. In the present timepiece, on the contrary, and as will appear later, the years cam is pivotally mounted on the month star and therefore moves relative to the dial throughout the year, according to a construction modern and proven of this kind of mechanism. It is therefore a question here of solving a problem which did not arise in connection with the cited patent, and which consists in making the indication of the cycle of the four years depend on the position of a cam of the years which moves. in turn continuously relative to the dial.

The solution to this problem is indicated in the means which appear in the claims.

• La fig. 1 est une vue de dessus de l'indicateur des mois et de l'indicateur de cycle de quatre ans selon une première variante d'exécution de l'invention;
• la fig. 2 est une coupe de mécanisme tel qu'il apparaît en fig. 1;
• la fig. 3 est une vue de dessous de mécanisme selon la fig. 2 quand la planche de calendrier a été enlevée;
• la fig. 4 est une vue de dessus de l'indicateur des mois et de l'indicateur de cycle de quatre ans selon une seconde variante d'exécution de l'invention; et
• la fig. 5 est une coupe partielle du mécanisme tel qu'il apparaît en fig. 4.

The invention will now be explained with the aid of the description which follows and of the drawings which illustrate by way of example in which:

• Fig. 1 is a top view of the month indicator and the four-year cycle indicator according to a first variant of the invention;
• fig. 2 is a sectional view of a mechanism as it appears in FIG. 1;
• fig. 3 is a bottom view of the mechanism according to FIG. 2 when the calendar board has been removed;
• fig. 4 is a top view of the month indicator and the four-year cycle indicator according to a second variant embodiment of the invention; and
• fig. 5 is a partial section of the mechanism as it appears in FIG. 4.

There is no question of describing here in detail the operation of a perpetual calendar mechanism. The interested reader will find for example in the work of B. Humbert entitled "Modern watches-calendar" all the information useful for the understanding of the functioning of such a mechanism (Edition Scriptar SA, Lausanne, 1953, p. 35-46 ). It should however be mentioned that a perpetual calendar watch does not require manual correction of the date display at the end of the months counting thirty-one month. Similarly, every four years, at the advent of the leap year and in February, the watch will display the number twenty-nine before indicating the first of March. The date display (not shown in the drawings which accompany this description) can be done by means of a hand or even by means of a disc, the numerical indications of which appear in turn through a window. The needle or the disc, capable of making a turn in thirty-one days, is controlled by a so-called multiple rocker of which one of the spouts is controlled by a cam which makes a turn in twelve months and which will be discussed below.

Fig. 1 is a top view of a first alternative embodiment of the invention. On the dial 1 of the watch are printed the indications 2 relating to the months of the year and distributed over a circumference. The month 3 needle is chased on a month 4 star cannon which pivots on a post 5.

If we now refer to fig. 2 which is a section through FIG. 1, we see that the post 5 is secured to the calendar board 40 for example by hunting. On the barrel 4 is driven the star 6 which thus rotates freely around the tenon 5 which serves as its pivot axis. A month cam 7 is fixed on the star by means of screws 8. On this cam the spout of the multiple rocker rests to slave the date hand to the current month as was mentioned above. The beak of the rocker is symbolized in figs. 1 and 2 by arrow 14 while the servo mechanism of the date indicator is not shown. As best seen in fig. 1, the month star 6 carries twelve teeth and the cam 7 has solid parts 9 corresponding to the months of thirty-one days and shallow notches 10 corresponding to those of thirty days. In the cam 7 is made an opening 11 situated between the solid parts corresponding to the months of January 9 'and March 9 ". In this opening 11 is housed the cam from the 12s which is presented as a small rectangle forming part of a mobile 13 pivoting on the star 6. It is apparent that three sides of the rectangle are equidistant from the pivot point 15 while the fourth, which is here in the form of an arc, is further away. In February, the spout 14 is opposite the opening 11. If, at this moment, is turned towards the outside of the opening 11. If at this moment, is turned towards the outside of the opening 11 one of the three flanks closest to the center, the beak 14 will have its maximum penetration, which will correspond to a month of February of twenty-eight days. If, on the contrary, it is the flank in arc of circle which is directed towards the outside of the opening 11, as drawn in Fig. 1, the spout 14 will be in a situ ation of intermediate penetration between the shallow notch 10 and a flank close to the pivot axis of the cam of the 12 years: this will correspond to a month of February of twenty-nine days. In the first case considered above, there will be a change from the date indicator from February 28 to March 1, while in the second case, representing the leap year, the change to March 1 will be on the - new February. Thus, there is a succession of three normal years and one leap year.

It is therefore necessary that the cam 12 makes one revolution in four years, which generally is obtained in the following manner. The cam 12 is provided with a barrel 16 cut in a square which pivots freely in the star 6. On this square is adjusted a Maltese cross 17 with four entrances held integral with the cam of the 12 years by a screw 18. As we see it in fig. 3, a finger from the 26s is chased on the tenon 5. When the star rotates, the finger 26 therefore remains stationary. As the star 6 makes one turn per year, it will be understood that the Maltese cross 17 and therefore the cam of the 12 years which is linked to it will only turn a quarter of a turn during the same period of time. Thus, every four years, the arcuate side of the cam 12 will be placed in front of the opening 11, as shown in fig.1.

As already mentioned, the present invention takes advantage of the state of the art which has just been exposed to control a four-year cycle indicator by the mobile 13 pivoting on the star and of which the cam of the 12 years.

A first alternative embodiment of the invention will now be explained with the aid of FIGS. 1, 2 and 3. The mechanism first has a first ring 20 which is integral with the month star 6. It can be seen that the screws 8 are screwed into a thread formed in the ring 20 in such a way that when they are tightened, ring 20, cam 7 and star 6 form a rigid assembly which performs one revolution per year and which drives in its rotation the month needle 3, said needle being integral with the barrel 4 itself integral with the star 6.

The mechanism then has a second ring 21 arranged to rotate freely inside the first ring 20. This second ring is driven on a pinion 22 mounted freely on the barrel 4. The teeth 23 of the pinion 22 mesh with a toothing 24 carried by the mobile 13 pivoting on the star 6. The second ring constitutes the cycle indicator of four years proper and happens to be controlled by the mobile 13.

During most months of the year, from February to September, the rounding 50 of a tooth of the Maltese cross 17 is in contact with the circular part 25 of the finger 26 (see fig. 3). The Maltese cross is thus immobilized in relation to the star. During this period of time therefore, the second ring 21 will rotate in synchronism with the first ring 20 because of the coupling existing between the toothing 24 and the pinion 22.

From the month of October, the finger 26 begins to enter an entry 27 of the Maltese cross 17. The mobile 13 is then rotated in the direction of the arrow 28 if the star rotates in the direction of the arrow 29. In the middle of its revolution, that is to say between the months of November and December, the Maltese cross occupies the position illustrated in fig. 3. In January, the entry 27 of the Maltese cross 17 will leave the finger 26 and in February the round 50 of the Maltese cross is again in contact with the circular part 25 of the finger 26. Thus , the Maltese cross 17 and the mobile 3 which is linked to it will have made a quarter turn in the direction of the arrow 28 and will have driven, via the toothing 24, the pinion 22 and the second ring 21 by a quarter turn In the opposite way.

In a practical execution and as can be seen in fig. 1, the visible faces of the rings 20 and 21 are arranged in the same plane as the visible face of the dial 1. The visible face of the first ring 20 is divided into four areas, the first marked "1", the second marked "2", the third marked "3" and the fourth marked "leap". An index 30 is affixed to the visible face of the second ring 21. From February to September, the month hand 3, the first ring 20 and the second ring 21 rotate in synchronism in the direction of the arrow 41 The index 30 remains permanently centered in front of the range marked "leap" of the first ring 20, thereby indicating that the current year is a leap year. As soon as the needle 3 reaches the month of October, the second ring 21 begins to rotate in the opposite direction to the first ring 20 and in the direction of the arrow 31. When the needle 3 has reached the month of February, the index 30 will be centered on the indication "1" indicating a first pre-leap year.

It will be noted in connection with this embodiment that the hand 3 could be replaced by an index affixed to the first ring 20, said index then playing the role of indicator of the months.

We will now describe with the aid of figs. 4 and 5 a second alternative embodiment of the invention.

In fig. 5, which is a partial section of the mechanism according to this second variant, we find the month star 6 and the mobile 13 pivoting on the star. This mobile also includes a cam from the 12s and a Maltese cross (not shown) which is attached to it by means of the screw 18. This arrangement is the same as that which has been explained in connection with the first three figures. On the star of months 6, riveted on the barrel 4, is screwed a single ring 35. The assembly thus formed pivots on the tenon 5.

In this variant, the cam from the 12s is surmounted by an indicator disc from the 36s which is chased there and therefore rotates with it. The ring 35 is provided with a window 37 which reveals information carried by the disc. According to the explanations that were given above, the disc 36 will make a revolution in four years and present through the window 37 four different tracks, the change of track taking place over four months (October to January) so that the indication of the current year appears clearly when we approach the month of February. Thus, the indicator disc for years 36 turns on itself at each change of year and revolves around tenon 5 in a year driven by the star 6 and the ring 35 secured to said star.

Fig. 4 is a top view of the indicator according to this second variant. The visible surface of the ring 35 is at the same level as the top of the dial 1 of the watch. This dial bears the indications 2 of the months. The month indicator here is an index 38 affixed to the ring, but it could be a needle driven out of the barrel 4 (see fig. 5), as was the case in the first variant described above. The disc 36 contains four pieces of information distributed at equal distance from each other, three of which relate to the pre-leap years and marked "1", "2" and "3" and the fourth of which relates to the leap year and marked "BIS". One of this information appears in the window 37 and then changes with each revolution of the index 38.

It will be understood that this second variant of embodiment directly takes advantage of the rotation of the mobile 13 pivoting on the star 6 to display the current year since it is no longer necessary to equip the mechanism with a pinion meshing with a toothing as in the first variant. However, this second variant requires a ring 35 of large diameter so that the indications carried by the disc 36 are still legible in the window. This drawback could be avoided by replacing numbers and letters with colored dots, for example red for the leap year, white, black and blue for the pre-leap years.

In this second variant, the disc 36 could be replaced by a needle whose axis would be integral with the mobile 13 and would cross the ring 35. In this case, the indications "1", "2" and "3" and "leap "Would be affixed directly to the ring 35.

Claims (5)

1. Perpetual calendar mechanism for a timepiece comprising a month star (6) effecting one revolution per year, a month cam (7) fixed to the month star and exhibiting full radius segments (9) corresponding to thirty-one day months, shallow notches (10) corresponding to thirty day months and an opening (11) between the full radius segments corresponding to January (9') and March (9"), a rotatable assembly (13) journalled on the month star and including a year cam (12) arranged to effect one revolution every four years, said year cam exhibiting four sides which appear successively in said opening, a month indicator (3) and a four year cycle indicator, characterized by the fact that the four year cycle indicator (21, 36) is controlled by the rotatable assembly (13) journalled on the month star (6).

2. Perpetual calendar mechanism as set forth in claim 1, characterized by the fact that it further includes a first ring (20) fixed to the month star (6), that the month indicator is a hand (3) borne by a pipe (4) fixed to the star and that the four-year cycle indicator comprises a second ring (21) fixed to a pinion (22) journalled on the pipe, said second ring being able to turn freely within the first ring and said pinion being arranged to mesh with teeth (24) borne by the rotatable assembly journalled on the star.

3. Perpetual calendar mechanism as set forth in claim 2, characterized by the fact that the first (20) and second (21) rings exhibit two visible surfaces substantially coplanar with the visible surface of the timepiece dial (1), the visible surface of the first ring being divided into four sectors the first three of which bear information concerning normal years and the fourth bears information concerning leap-year, the visible surface of the second ring bearing an index (30) marker which passes from one sector to the next with each full revolution of the month hand.

4. Perpetual calendar mechanism as set forth in claim 1, characterized by the fact that it further comprises a ring (35) fixed to the month star, that the month indicator is an index (38) placed on the periphery of the ring and that the four-year cycle indicator comprises a disc (36) located under the ring and fixed to the rotatable assembly (13) journalled on the star (6), said ring having an opening (37) through which appear informations borne by the disc.

5. Perpetual calendar mechanism as set forth in claim 4, characterized in that the ring (35) exhibits a visible surface substantially coplanar with the visible surface of the timepiece dial (1) said disc (36) bearing four items of information three of which concern normal years and the fourth concerning leap-year, said information items appearing successively in said opening (37) with each full revolution of the month indicator index (38).

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