EP2249215B1 - Chronograph watch with instantaneous display of the fractions of a second - Google Patents

Description

The present invention relates to a device for the instantaneous display of fractions of a second, on a separate counter in a mechanical chronograph watch, only when stopping the timing, or when momentarily interrupts the timing when said chronograph watch is equipped with a jumper.

In chronograph watches with mechanical drive, there is usually a central seconds hand driven by the chronograph wheel when pressing the start button, this needle advancing step by step at the frequency imposed by the sprung balance. If this frequency is 18'000 vibrations per hour, the needle will advance 5 steps per second, an angle of 1.2 ° per step. With a dial of the order of 30 mm, this means that at each step the tip of the seconds hand will move by an arc of about 0.3 mm, which can be distinguished by naked eye if there is an additional graduation between each second. It will be admitted, however, that the reading of a time measured to a fifth of a second requires some attention, and that the reliability of the reading also depends on the care with which the graduations have been produced or traced on the dial, as well as the precision with which the dial feet have been adjusted.

To overcome the above drawbacks, the manufacturers have proposed to equip mechanical chronograph watches with a device called "second lightning". The principle is to display on the dial fractional seconds on a separate meter by means of a small needle, permanently driven by a multiplicative gear train, said small needle making each second a complete turn, or even 4 or 5 turns depending on the complexity of the gear train. Such a device makes reading easier, and allows a precision to the tenth of a second, but has the disadvantage of requiring a surplus of mechanical energy to drive during the time of the gear train and the small amount of time. needle. This additional energy resource can be obtained by increasing the dimensions of the barrel, or by adding a second barrel, which has the disadvantage of making the construction of the movement more complex, and increase the weight and dimensions of the chronograph watch. .

When the chronograph watch makes it possible to make intermediate stops, stopping the jumper does not stop the lightning, so that the Reading an intermediate time does not have the precision of the time read after the complete stop of the timing.

The document EP 1 024 416 describes a chronograph watch according to the preamble of claim 1.

The invention therefore aims at overcoming the drawbacks of the aforementioned prior art by providing a mechanical chronograph watch comprising a mechanism making it possible to display instantly, after temporarily or permanently stopping the timing, the fractions of seconds to be added to the values indicated by the catcher or the second hand in the center and by the other counters. Throughout the duration of the timing, the device according to the invention is designed so that the meter displaying the fractions of a second is completely separated from the kinematic chain, which has the advantage of considerably reducing the supply of mechanical energy that was necessary. according to the aforementioned prior art, while providing a display having excellent accuracy and excellent readability, both for a final time and for intermediate times.

For this purpose, the invention relates to a chronograph watch according to claim 1.

Thus, throughout the duration of the timing, the fractional seconds counter is disconnected from the kinematic chain, and the additional energy for the display of fractions of a second is provided by the rewinding of a spring when performing resetting the counter.

As will be seen in the detailed description, each elementary cam may be formed by an inclined plane or by a succession of stages each corresponding to a fraction of a second.

The circular cam can be driven directly by the chronograph wheel being concentric with said wheel and then comprises 60 elementary cams of angular aperture α = 6 °. In order to increase the area swept by the fractional second hand, the circular cam can also be driven indirectly via a pinion engaged with the chronograph wheel in a multiplicative ratio k such that k • x = 60.

The fractions of a second needle can be driven directly by the probe arm or by a secondary arm secured thereto. It can also be driven indirectly via a rack secured to said feeler arm and whose toothed sector meshes with a pinion itself driving the fractional second needle.

It will also be observed that, in order to allow the free rotation of the cam during the timing, the probe must be located outside the envelope of rotation of the cam, which causes the fractional second needle to be positioned on a neutral position "N" preceding the 0 position of the counter. However, by minimizing the distance between the probe and the envelope, the "N" and "0" positions can be visually confused, which is particularly advantageous for a circular dial meter.

The mechanism and the timing control means (start, stop and reset) may be those known from the prior art, such as a column wheel acting on a lever secured to the feeler arm.

• la figure 1 est une vue de dessus d'une montre-chronographe selon l'invention;
• la figure 2 est une représentation agrandie au niveau de la roue de chronographe d'un premier mode de réalisation d'un mécanisme selon l'invention en position de mise en marche;
• la figure 3A est une représentation agrandie d'une portion d'une première variante du mécanisme de la figure 2 au niveau de la flèche III;
• la figure 3B est une représentation agrandie d'une portion d'une deuxième variante du mécanisme de la figure 2 au niveau de la flèche III;
• la figure 4 est une représentation agrandie au niveau de la roue de chronographe d'un deuxième mode de réalisation d'un mécanisme selon l'invention en position de mise en marche;
• la figure 5 représente le même mécanisme que celui de la figure 4 en position arrêt;
• la figure 6 représente le même mécanisme que la figure 4 en position de remise à zéro;
• la figure 7 représente un troisième mode de réalisation, illustrant en outre des variantes d'un mécanisme selon l'invention;
• la figure 8 est une représentation schématique agrandie d'un quatrième mode de réalisation lorsque le dispositif selon l'invention est appliqué à une aiguille de rattrapante;
• la figure 9 est une représentation schématique d'une variante du mécanisme représenté à la figure 8, et
• la figure 10 est une représentation agrandie d'une came élémentaire au niveau de la flèche X de la figure 9.

Other characteristics and advantages of the present invention will appear in the following description of several examples, given by way of illustration and without limitation, with reference to the appended drawings in which:

• the figure 1 is a top view of a chronograph watch according to the invention;
• the figure 2 is an enlarged representation at the level of the chronograph wheel of a first embodiment of a mechanism according to the invention in the start-up position;
• the figure 3A is an enlarged representation of a portion of a first variant of the mechanism of the figure 2 at the level of arrow III;
• the figure 3B is an enlarged representation of a portion of a second variant of the mechanism of the figure 2 at the level of arrow III;
• the figure 4 is an enlarged representation at the level of the chronograph wheel of a second embodiment of a mechanism according to the invention in the start-up position;
• the figure 5 represents the same mechanism as that of the figure 4 in the off position;
• the figure 6 represents the same mechanism as the figure 4 in reset position;
• the figure 7 represents a third embodiment, further illustrating variants of a mechanism according to the invention;
• the figure 8 is an enlarged schematic representation of a fourth embodiment when the device according to the invention is applied to a split-second needle;
• the figure 9 is a schematic representation of a variant of the mechanism represented in figure 8 , and
• the figure 10 is an enlarged representation of an elementary cam at the level of the arrow X of the figure 9 .

According to the embodiment shown in figure 1 a chronograph watch according to the invention comprises a dial 2 indicating the current time by means of an hour hand 3, a minute hand 4, and a small seconds hand 5 off-center on a dial 15 located at 6 o'clock. For the timing function, the watch also includes a central seconds hand 6a, a counter 17 indicating the fractions of a second by means of a hand 7 and a counter 18 indicating the minutes by means of a hand 8. The watch chronograph comprises on its middle 9 a crown 12, a pusher 11 for starting and stopping and a pusher 13 for reset. In known manner, the pushers 11 and 13 could be replaced by a single triple action pusher. There is also shown a splitter needle 6b whose stopping or walking is controlled by the split-seconds pusher 16 and on the counter 17 an additional second-fraction needle when the chronograph watch is provided with a split-second. The chronograph watch obviously includes a chronograph movement of frequency F, not shown as being well known to those skilled in the art.

Referring now to Figures 2, 3A and 3B a first embodiment of a mechanism is described below when the chronograph watch does not have a catch-up and therefore does not comprise the pusher 16 shown in FIG. figure 1 . To the figure 2 corresponding to a starting position, only parts useful for understanding the invention have been shown. Stop and reset positions will be explained later with reference to figures 4 , 5 and 6 corresponding to a second embodiment.

The driving element is constituted by the chronograph wheel 10 which supports and drives a circular cam 20 in the form of a ring, said cam 20 being formed by a sequence of x elementary cams 22, having an angular aperture α corresponding to a second, that is 6 °. These elementary cams 22 are intended to cooperate with a feeler arm 27. The circular cam 20 may be a separately manufactured piece and then concentrically fixed on the chronograph wheel 10. It may also be integral with the chronograph wheel 10.

As we see on the figure 3A an elementary cam 22 is formed by a succession of stages 23i each corresponding to a fraction of a second. In the example shown in figure 3A , we can count 5 stages corresponding respectively to 0, 1/5, 2/5, 3/5 and 4/5 of a second to add to the timed time. For this purpose, for example, a frequency corresponding to 18,000 vibrations per hour is chosen, ie 5 strokes per second.

In the variant shown in figure 3B an elementary cam 22 simply comprises an inclined plane 25, and the circular cam 20 is formed by a solid disc.

The circular cam 20, respectively each elementary cam 22, is intended to receive, when stopping the timing, the probe arm 27 pivoted on an axis 28, and the beak 29 abuts on a stage 23i or on the inclined plane 25 by rotating the second fraction needle 7 which is secured thereto to position it opposite a scale 0, 1, 2, 3 or 4 of the counter 17. The counter 17 comprises, before the graduation O, a graduation "N" corresponding to a neutral position in which the nozzle 29 of the probe arm 27 is completely clear of the cam 20 by allowing the free rotation of the chronograph wheel 10. By minimizing the distance between the end of the nozzle 29 and the outermost edge of the cam 20, one can have the graduations O and N practically merged.

As represented in figure 1 it is also possible to mask the graduation N by means of an appropriate cut in the dial 2.

The probe arm 27 is kept spaced from the cam 20 by a control arm 31 whose end comprises a pulse plane 32 held by a spring (not shown) resting on a column 33i of a column wheel 30 comprising drive teeth 34i. The probe arm 27 is further provided with a secondary arm 35 having at its end a pin 36 intended to cooperate with a latch 40 pivoted on an axis 41, said latch 40 being held in the position represented by a retaining pin 42 and enabling the counter 17 to be reset by means of a control finger 43, as will be explained with reference to the Figures 4 to 6 .

The latch 40 also comprises two arms 44, 46 having at their ends two hammers 45, 47 for resetting the cores (not shown) of the other counters.

Referring now to figures 4 , 5 and 6 a second embodiment is described below in which the same or similar parts are designated by the same references.

The figure 4 , which corresponds to the figure 2 in the start-up position, there are two essential differences in the indirect drives of the cam and fractional second hand.

It can be seen firstly that the circular cam 19, formed by the sequence of x elementary cams each corresponding to a second, is no longer directly supported by the chronograph wheel 10, but by a drive pinion 21. ₂ teeth engaged with the toothing 14 of the chronograph wheel having n ₁ teeth, that is to say in a multiplicative ratio of gears k = n ₁ / n ₂ . This ratio k must be an integer divisor of 60, so that a complete revolution of the drive pinion 21 corresponds to an integer x of seconds, that is to say in fact to the number x of cams In other words, the number x of elementary cams, multiplied by the gear ratio k, must be 60 seconds, which corresponds to the relation kx = 60.

In the example shown, it can be seen that the cam 19 has 6 elementary cams 22, which corresponds to a gear ratio k = 10, which makes it possible for example to have a chronograph wheel 10 with n ₁ = 160 teeth and a drive pinion 19 with n ₂ = 16 teeth. Other choices are obviously possible. In particular, it would be advantageous to have a chronograph wheel n ₁ = 180 teeth so as to be able to build a mechanism having from 2 to 6 elementary cams, simply by choosing driving gears 19 having respectively 6, 9, 12, 15 or 18 teeth.

This embodiment also has the advantage of providing elementary cams having a large angular aperture α (60 ° in the example shown) making it easier to arrange the stages 23i or the inclined plane 25. It also makes it possible to have 23i stages (respectively a tilted plane 25) deeper by providing a greater clearance to the feeler arm 27 and correlatively to the fraction of second hand 7, in the case where it would be, as in the first embodiment, integral with the 27. The graduations of the counter 17 can then be further spaced, which facilitates reading. In the example shown, we see that the graduations are from 0 to 5, which corresponds to a fractionation in 1/6 of a second. For this purpose, each elementary cam 22 has 6 stages 23i and a frequency of 21600 alternations per hour is chosen.

This second embodiment also differs from that first described in that the fraction of second hand 7 is no longer driven directly by the feeler arm 27, but indirectly by a rack 37 secured to said feeler arm 27, and the toothed sector 38 meshes with a pinion 39 supporting the fractional seconds hand 7 and driving it in rotation. The addition of the rack 37 has the advantage of being able to further amplify the movement of the second fraction needle 7 and to give more freedom in the positioning of the counter 17 on the dial 2.

To the figure 5 the position of the mechanism has now been shown when stopping the timing. The column wheel 30 pivots and, under the action of the spring 32, the spout 31a of the control arm 31 falls between the two columns 33 _i and 33 _{i + 1} in releasing the probe arm 27 whose tilting will be limited by the arrival of its nozzle 29 abutting on a stage 23i of an elementary cam 22 of the cam 20. This tilting movement also causes the rack 37 whose toothed sector 38 goes rotate the pinion 39 controlling the displacement of the needle 7 on the dial 17 opposite a scale corresponding to the stage 55 _i on which the probe 37 has come into abutment.

The figure 6 represents the position of the mechanism when performing the reset, that is to say in fact when the needles 6 and 8 are reset to zero by means of the hammers 45 and 47 acting on cores (not shown) and the fractional seconds hand 7 in neutral position N. This operation is performed by pressing the pusher 13 to pivot the lever 40 and exert, via the finger 43, a pressure on the pin 36 of the arm 35 to tilting the rack 37 and maintain, without intervention of the column wheel 30, in the rest position in which the nozzle 29 of the probe arm 27 again allows free rotation of the cam 19. The needle 7 is returned to position neutral N by rotating the pinion 39 by the toothed sector 38 of the rack 37.

When it is desired to perform a new timing, the column wheel 30 advances one step, which causes both the release of the pin 36, and the locking of the end 31a of the arm 31 on a column 33i of the column wheel 30, as shown in FIG. figure 4 .

The figure 7 represents a second embodiment which illustrates possible variants of the fractional second display mechanism according to the invention.

In the embodiment shown, it can be seen that the cam 19 has 4 elementary cams 22 (x = 4), which corresponds to a gear ratio k = 15, and makes it possible, for example, to have a chronograph wheel 10 to 180 teeth (n ₁ = 180) and a drive gear 21 with 12 teeth (n ₂ = 12). As can be seen, by decreasing the number of elementary cams 22, the possibility of splitting a second is increased. In the example shown in figure 7 it can be seen that each elementary cam has 10 stages 23 _i , which corresponds to a fractionation in tenths of a second, provided, of course, that a frequency of 36000 vibrations per hour is used. With this same frequency could also be designed an elementary cam having only 5 stages for a timing to 1/5 second and to correct the default start interlocking.

The same result could be obtained with a frequency of 28800 vibrations per hour for a timing of 1/4 seconds.

According to another variant represented in the figure 7 it can be seen that the drive pinion 39 is replaced by a multiplicative gear train 24, 26, so that the fractional seconds hand 7 driven by the driven pinion 26 can scan the entire circumference of a circular dial. This construction also has the advantage of reversing the direction of rotation of the needle 7 and thus to provide a display in the clockwise direction.

The figure 8 represents a fourth embodiment in which the device according to the invention is also applied to the mechanism of the catch-up needle 6b, thus making it possible to read an intermediate time timed with the same precision of fractions of a second as a final time. The similar or identical parts are designated by the same references as those indicated in the previous embodiments.

A cam 20 comprising elementary cams 22 is driven by a chronograph wheel 10, itself engaged with that which drives the second hand to the center 6a, and can be detached from it by known devices in a split-seconds chronograph watch. The device also comprises a column wheel 30a provided with columns 33i and teeth 34i, as previously described. The rotation of this column wheel 30a is controlled by a device (not shown) actuated by the pushbutton 16.

The device also comprises a probe arm 27 extended by a control arm 31, pivoted on an axis 28, said probe arm 27 having a nozzle 29 whose end comes to fall into an elementary cam 22, when the actuation of the pusher 16 is drop a lug 32 of the control arm 31 between two columns 33i of the column wheel 30 under the action of a spring (not shown). The control arm 31 also comprises, as in the second embodiment, a rack 37 whose toothed sector 38 meshes with a pinion 39 driving the second fraction needle 7b of the catcher 6b in front of a counter scale. fractions of a second 17.

The device differs from those previously described essentially in that the stopping of the chronograph wheel 10 driving the cam 20 is caused by the tweezers clamp 50. In the example shown, the clamp 50 is constituted by two elbow arms 51 a, 51b pivoted at their bends respectively on pads 52a, 52b and shown in FIG. figure 8 in the position where their ends bear on the toothing 14 of the chronograph wheel 10 under the action of a spring (not shown).

One of the arms 51a is a control arm provided, at its end not acting on the toothing 14, a screw 54 whose head acts on the end corresponding to the other arm 51b, to tilt at the same time as the control arm 51a. Advantageously, the screw 54 is an eccentric screw for adjusting the pressure exerted by the clamp on the toothing 14.

This open / closed maneuver of the clamp 50 is controlled by the column wheel 30 whose columns 33i cooperate with a spout 55 terminated by a flat portion 56 of the control arm 51a of the clamp 50 to open it. Conversely the spaces between the columns 33i allow the spout 55 to fall between two columns and ensure the closure of the clamp 50.

The fractional second hand 7b for the timing of an intermediate time by means of the catch-up 6b and the fractional second hand 7a for the timing of a final time by means of the second hand in the center 6a can be on the same counter 17, as shown in FIG. figure 1 since these needles are driven by mechanisms based on the same principle, but separated. It is also possible to design this display of fractions of a second on two separate counters, the counter linked to the splitter 6b being for example positioned near the split-second push-button 16 and the minute counter 18 then being moved to another place on the dial.

The Figures 9 and 10 represent a variant of the second fraction device for a rattrapante previously described with reference to FIG. figure 8 . It differs in that the display of fractions of a second is performed on a counter 17b with a circular dial for which the kinematic link (not shown) can be of the type of any of the previously described links. It also differs in that each elementary cam 22 corresponds to 2 seconds, that is to say to an angular step α = 12 °, and comprises a double number of stages 23i. Thus, when the tip 29 of the feeler arm for example falls on the 2nd stage by stopping the jumper, the needle 7b is positioned in front of the indication 20 of the counter 17a. If the spout 29 falls on the 8th stage, the needle 7b makes a complete revolution and is then positioned in front of the indicator 30 of the counter 17a. This construction has the advantage of facilitating the machining of the stages 23i of the elementary cams 22 since the angle α is larger. It is obvious that other choices are possible provided the number of seconds corresponding to an elementary cam is an integer divisor of 60. This variant has just been described with reference to the counterclockwise for the timing of an intermediate time but can obviously be applied to the timing of a final time.

It is obvious that one skilled in the art can make other modifications to the mechanism that has just been described without departing from the scope of the invention, for example by combining together the variants that have been mentioned.

Claims (18)

1. Chronograph watch comprising a chronograph movement with a time base of frequency F, start, stop and return-to-zero control means (11, 13), an analogue display dial (2) using a centre seconds hand (6) driven by a chronograph wheel (10) which also drives, via gear trains, the hands (8) of other counters (18) and a hand (7) of a counter (17) comprising a graduation in fractions of a second, the fraction-of-a-second hand (7a) being driven in rotation by a sensing arm (27), pivoted on a plate or a bridge of the movement, whose tilting is controlled by chronograph stop means (11) and whose amplitude of displacement is controlled by its beak (29) coming to abutment on a circular cam (19, 20) driven by the chronograph wheel (10) and comprising x elementary cams (22) of angular aperture α each corresponding to an integer number of seconds that is a divisor of 60, said elementary cams (22) all having the same contour determining the displacement of the sensing arm (27) and allowing a second to be divided into fractions of a second, characterized in that the return-to-zero means of the fraction-of-a-second counter (17) are formed by a lever (40) acting on a pin (36) fixed on the sensing arm (27) or on an additional arm (35) integral with said sensing arm (27).
2. Chronograph watch according to claim 1, characterized in that the watch also includes a fly-back hand (6b), whose start/stop is controlled by a separate push-button (16) to display, by means of a second hand (7b) of the fraction-of-a-second counter (17), or of an additional counter, intermediate measured times with a mechanism similar to that of the final time and with the same precision.
3. Chronograph watch according to claims 1 or 2, characterized in that the cam (20) is driven directly by the chronograph wheel (10), while being concentric and integral with said wheel (10), and comprises 60 elementary cams (22) of angular aperture α =6°.
4. Chronograph watch according to claims 1 or 2, characterized in that the cam (19) is driven indirectly via a pinion (21) in mesh with the chronograph wheel (10) in a multiplication ratio k such that k·x = 60.
5. Chronograph watch according to claim 4, characterized in that the cam (19) is formed of a number of elementary cams (22) comprised between two and six.
6. Chronograph watch according to claims 1 or 2, characterized in that the sensing arm (27) or a secondary arm integral with said sensing arm (27) carries a finger (7a) acting as the fraction-of-a-second hand.
7. Chronograph watch according to claims 1 or 2, characterized in that the fraction-of-a-second hand (7) is driven indirectly by the sensing arm (27) via a rack (37) integral with said sensing arm (27), and whose toothed sector (38) meshes with a pinion (39) driving said fraction-of-a-second hand (7).
8. Chronograph watch according to claim 7, characterized in that the drive pinion (39) of the fraction-of-a-second hand (7) is replaced by a multiplying gear train (24, 26), said hand (7) being driven by a driven pinion (26).
9. Chronograph watch according to claims 1 or 2, characterized in that each elementary cam (22) is formed by an inclined plane (25).
10. Chronograph watch according to claims 1 or 2, characterized in that each elementary cam (22) is formed by a series of stages (23i) each corresponding to a fraction of a second.
11. Chronograph watch according to claim 10, characterized in that the frequency F determines the maximum number of stages (23i).
12. Chronograph watch according to claim 11, characterized in that the actual number of stages (23i) corresponding to a determined fraction of a second is the maximum number of stages (23i) or a sub-multiple thereof.
13. Chronograph watch according to claims 1 or 2, characterized in that the means for starting and stopping the time measurement comprise a column wheel (30) acting on a lever (31) integral with the sensing arm (27).
14. Chronograph watch according to claim 13, characterized in that the stopping and restarting of the fly-back hand (6b), are caused by a clamp (50) controlled by the column wheel (30).
15. Chronograph watch according to claim 14, characterized in that the clamp (50) is formed by two arms (51 a, 51 b) pivoted on studs (52a, 52B), one of the arms (51 a) being a control arm comprising a screw (54) whose head drives the other arm (21 b) and comprising a beak (55) ending in a flat portion (56) on which the columns (33) of the column wheel (30) act.
16. Chronograph watch according to claim 15, characterized in that the screw (54) is an eccentric screw for adjusting the pressure of the clamp (50) on the toothing (14).
17. Chronograph watch according to any of claims 1 or 2, characterized in that a graduation O of the fraction-of-a-second counter (17) is preceded by a neutral graduation N corresponding to the chronograph stop position in which the beak (29) of the sensing arm (27) is completely released from the cam (19, 20).
18. Chronograph watch according to claim 17, characterized in that the graduations 0 and N are practically coincident.

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