EP0772104A1 - Timepiece with a chronograph mechanism - Google Patents

Abstract

Counters for seconds ,minutes and hours are solidly attached to rotating elements (18,38,41). A clutch mechanism (17) is able to engage the rotating elements with a driven wheel train selectively using a pillar wheel and sprung arms (50,44,45) which operate periodically to displace a clutch disc axially. The clutch mechanism (17) when it operates drives the rotating element representing seconds (18) and this drive is further transmitted to the minutes and hours elements (38,41) through gear trains (35,37,38,35',40,40',41). An indexing pawl (51) is lockable on to a countershaft (37) by a peg in the declutched position.

Description

The present invention relates to a timepiece with a chronograph mechanism, comprising seconds, minutes and hour counters, having three respective indicator members each secured to a rotary mobile, clutch means for selectively setting engaged these rotary mobiles with a drive train for this timepiece, a device for controlling these clutch means and a mechanism for resetting these indicator members to zero.

In the chronograph mechanisms of the prior art, a first gear mechanism is used for counting the minutes and seconds and is arranged on one side of the movement, generally that which carries the bridges. A second gear mechanism driving the hour counter indicator is located on the other side, that is to say the one adjacent to the dial.

The place taken by these gear mechanisms is important and the surface occupied can be evaluated in general at 50% respectively 30% for these first and second gear mechanisms. The arrangement of the two sides of the movement also takes up space, so that such chronographs either increase the general volume of the timepiece or reduce the volume available for the other vital elements of this timepiece , that is to say, the barrel, the balance and the automatic winding mechanism. However, the volume of the barrel determines the power reserve of the watch and the diameter of the balance determines its precision.

The fact that the counting of seconds and minutes on the one hand, and that of hours on the other hand, is carried out by two gear mechanisms independent of each other can, under certain conditions of use , train a mismatch between the indications of the minute counter and those of the hour counter.

This offset results from the cumulative counting of several time intervals during which the chronograph mechanism is alternately started and stopped several times without intermediate resets.

The minute counter indicator is driven by the chronograph seconds wheel, itself driven by the seconds wheel of the watch movement. As for the hour counter indicator, it is driven by the barrel. When the timing is interrupted, the drive cogs of the chronograph gear mechanisms are disengaged from them and continue to rotate.

Upon re-engagement, the toothing of a clutch wheel mounted on a rocker engages the toothing of the drive wheel. Since during the stop it continued to rotate, the two teeth are not necessarily in the engagement position when they engage with each other. Since the drive wheel is under the tension of the barrel spring acting on the entire kinematic chain between the barrel and the escapement, it is the gear mechanism of the chronograph counter which undergoes a slight angular movement to allow the penetration of the toothed wheels into one another. This slight rotation is imperceptible for the train of minute and second counters, given the large number of teeth which is precisely chosen high to reduce the angular displacement following the clutch. On the other hand, the toothing of the hour meter train is necessarily less fine, so that the angular offset is more noticeable. In the case of cumulative timings, the angular offsets can add up and eventually produce a visible and annoying difference between the position of the hand of the minute counter and that of the hour counter.

It has already been proposed to train the minute counter once a minute by using a finger capable of to retract, secured to a wheel making one revolution per minute, generally a return wheel intended to rotate the seconds and minutes indicators in the same direction.

When the counters are reset, this finger returns to its starting position by cutting the path of the teeth of the wheel that this finger normally drives. At the same time, this wheel, driven by the minutes mobile also returned to its starting position, turns in the opposite direction to return to its zero position. Therefore, during this double rotation in opposite directions, this finger can meet up to 15 teeth of this wheel and must retract with each tooth thus causing wear of both the teeth and the finger.

It has already been proposed to replace this type of clutch with a friction clutch between coaxial circular members, one of which is displaceable axially against the force of a spring which tends to apply them one against the other. This clutch device with axial displacement of the clutch members takes up space. Since it is placed on the axis of the chronograph seconds wheel, located at the center of the movement on which there are other mobiles belonging to the watch, (center wheel, floor) the height of the movement is is further increased. In addition, if it is a watch with automatic winding, the pivoting system of the oscillating winding mass is still superimposed on the aforementioned members on the central axis of the movement, leading to a watch whose thickness is significantly increased.

The object of the present invention is to remedy, at least in part, the above-mentioned drawbacks.

To this end, the subject of this invention is a timepiece with a chronograph mechanism according to claim 1.

The advantages offered by the solution which is the subject of the invention are numerous and significant. This solution makes it possible to reduce the number of parts of the chronograph mechanism compared to conventional mechanisms. This mechanism is therefore very compact. Due to the drive of the entire chronograph gear mechanism by a single member, this entire mechanism can take place on the same side of the movement. Decentering the clutch device makes it possible to reduce the bulk in the center of the movement, leaving room to add, if necessary, an automatic winding module, the pivoting of the oscillating mass of which is located in the center of the movement without any particular repercussions. on the height of it.

The simplification of the chronograph mechanism also goes in the direction of an increase in its reliability. The periodic drive of the indicator members of the hour and minute counters by the gear train of the timepiece also makes it possible to reduce the energy taken from this gear train for driving the chronograph mechanism. In addition, given the kinematic transmission connecting the hour and minute counters, only one indexing member is necessary, also reducing the energy required to drive this transmission.

Although some of the aforementioned advantages are more particularly associated with a mechanical timepiece, the invention is in no way limited to this type of timepiece. This timepiece could also be an electronic timepiece, in particular a quartz watch with rotary display, in particular with analog display. Similarly, in the case of a mechanical timepiece, it may or may not be automatic.

• La figure 1 est une vue générale en plan côté ponts du mouvement de cette pièce d'horlogerie;
• La figure 2 est une vue en coupe selon la ligne II-II de la figure 1;
• La figure 3 est une vue en coupe selon la ligne III-III de la figure 1.
• La figure 4 est une vue en plan partielle de la figure 1 illustrant seulement une partie du mécanisme de chronographe;
• La figure 5 est une vue en plan partielle de la figure 1 illustrant seulement une autre partie du mécanisme de chronographe.

The accompanying drawing illustrates, schematically and by way of example, an embodiment of the timepiece with chronograph mechanism, object of this invention.

• FIG. 1 is a general plan view on the bridge side of the movement of this timepiece;
• Figure 2 is a sectional view along line II-II of Figure 1;
• Figure 3 is a sectional view along line III-III of Figure 1.
• Figure 4 is a partial plan view of Figure 1 illustrating only part of the chronograph mechanism;
• Figure 5 is a partial plan view of Figure 1 illustrating only another part of the chronograph mechanism.

The timepiece illustrated in Figures 1 to 3 is a self-winding timepiece with chronograph mechanism. FIG. 1 illustrates the plate 1 with the location of the barrel core 2 and that of the balance wheel 3. It also illustrates the location of the winding stem fixed to the winding crown 4 as well as that of the two chronograph pushers 5 and 6 controlling the starting and stopping respectively the resetting of the chronograph.

In Figure 2 we see the barrel 7 and the center wheel 8 whose axis 9 carries the roadway 10 on which is driven the minute hand 11, the hour hand 12 being attached to the barrel wheel 13 FIG. 3 illustrates the same members with, in addition, the mean wheel 14, the pinion 14 'of which meshes with the center wheel 8. This mean wheel 14 meshes with the pinion 15' of the seconds wheel 15 carrying the needle of seconds off-center 16.

The rest of the mechanism of the timepiece, well known to those skilled in the art and outside the scope of the present invention will not be described here, insofar as this description is not necessary for its understanding.

It is from the seconds wheel 15 that the entire train of the chronograph mechanism object of the invention is driven periodically and on command. The axis of the seconds wheel 15 carries a pinion 15 "which meshes with a pinion 17 'pivoted freely on the axis of a clutch wheel 17 of the chronograph, this wheel 17 being integral with its axis 17a. The detail of the clutch mechanism associated with this clutch wheel 17 will be described below. The gear ratio between the pinions 15 "and 17 'is 1/1, so that the speed of rotation of the clutch wheel 17 is identical to that of the seconds wheel 15.

The clutch wheel 17 meshes with a wheel 18 which constitutes the second chronograph wheel and which has the same number of teeth as the clutch wheel 17, so that it rotates at the same speed as the clutch wheel 17 and, consequently, that the seconds wheel 15. Given the reversal of the direction of rotation of two wheels meshing with each other, the chronograph seconds wheel 18 therefore rotates in the same direction as the wheel 15 seconds from the work of the timepiece. The axis 18a of this second chronograph wheel 18 carries the second chronograph hand 19 and crosses the tubular axis 9 of the center wheel 8 with respect to which it pivots freely in bearings 20, 21, 22 secured respectively, of a bridge 23 carrying the chronograph train, of a bridge 24 of the train of the timepiece fixed on one face of the plate 1, the opposite face of which carries the dial 25, and of the tubular axis 9 of the wheel center 8.

The clutch wheel 17 also carries a second annular drive member in the form of an open ring 26, comprising a retractable finger 27 in the shape of a triangle projecting radially towards the outside of the ring (FIGS. 3 and 5). . This annular drive member 26 is pivotally mounted on a pin 28 driven into the clutch wheel 17. From this pin, the drive member 26 tapers to form a return spring 26a of the retractable finger 27 integrated into this member 26. Part 26a of the drive member 26 is housed in a recess 29 in the clutch wheel 17. The retractable finger 27 cuts the path of a first wheel 35 of the train of chronograph counters , so as to drive the latter at each revolution of the clutch wheel 17.

The pinion 17 'of the clutch wheel 17 is integral with a clutch disc 30 (fig 31) which continuously rotates with the pinion 17 in engagement with the seconds wheel 15. A ferrule 31 is driven out on the axis 17a of the clutch wheel 17. An elastic disc 32 is riveted on this ferrule and carries, at its periphery, a clutch ring 33. The elastic disc 32 resiliently applies the ring clutch 33 against the clutch disc 30. The latter drives this ring 33 and consequently the axis of the clutch wheel 17, in friction rotation. This axis 17a also carries a heart-shaped cam 34 for resetting the seconds chronograph wheel 18.

The train of chronograph counters is visible in Figures 1,2,4 and 5. The first wheel 35 of this train is pivotally mounted on a tubular member 36 (fig. 2) driven into the bridge 24 of the train of the piece d watchmaking. This wheel 35 driven at the rate of one revolution every 30 minutes meshes with a gear 37 which in turn meshes with a minute counter wheel 38 rotating at the same speed and in the same direction as the wheel 35, thanks to gear 37. The axis 38a of this wheel 38 carries the hand 39a of the minute counter. The connection between the wheel 38 and its axis 38a is frictionally to allow these two members an independent angular displacement beyond a certain torque.

The pinion 35 'of the wheel 35 meshes with an intermediate wheel 40 whose pinion 40' meshes with the hour meter wheel 41 whose axis 41a carries the indicator needle 39b of the hour meter. The connection between this wheel 41 and its axis 41a is, as for the minute counter wheel 38 also frictionally for the same reasons. Therefore, when zeroing the axes 38a and 41a can move angularly relative to the wheels 38 and 41.

Both the shaft 38a of the minute counter and that 41a of the hour counter are integral with a reset cam 42 respectively 43 in the shape of a heart.

As explained above, the elastic disc 32 of the clutch wheel normally applies the clutch ring 33 against the clutch disc 30, as illustrated in strong lines in FIG. 3. The ring clutch 33 is capable of being moved axially by deforming the elastic disc 32, as illustrated in thin lines in FIG. 3.

To this end, two rockers 44, 45 are pivotally mounted around two bearing screws 46, 47 (fig. 1 and 5). These rockers 44 and 45 are each provided with a finger 44a respectively 45a, the trajectories of which around the bearing screws 46, 47 intersect. A spring 48 exerts pressure on the finger 45a, which keeps the two rockers in position spaced from the clutch ring 33, a stop 49 serving to limit their movement. The lever 44 has a second finger 44b which penetrates between the columns of a column wheel 50 in the position separated from the rockers. This lever 44 also carries a dowel 44c which is, in the position illustrated in solid lines in FIG. 5, near an indexing jumper 51 engaged with the teeth of the reference 37.

The column wheel 50 is integral and coaxial with a ratchet wheel 52 (FIG. 1) engaged with a pawl 53 secured to one end of a rocker 54 pivoted about an axis 55. This rocker 54 is controlled by the chronograph on-off push-button 5. A return spring 56 is disposed under the rocker 54 and serves to return the latter to the rest position. The lever 54 has a clearance 54a in which a stop 57 is engaged and serves to limit the stroke of the lever 54 and therefore the angular displacement of the ratchet wheel 52, which is positioned by a spring pawl 58.

The reset push-button 6 is engaged with a first rocker 59 provided with a pin 60 which is engaged in an elongated opening 61 of a second rocker 62 of which a finger 62a is blocked or not by the column wheel 50 according to the angular position thereof. The rocker 59 is pivoted around a tenon 63, while the rocker 62 is pivoted around the stop 57 which therefore has two functions. A spring 64 ends in two inclined planes forming an obtuse angle between them. One of these planes presses against the ankle 60 of the rocker 59 and keeps it in the position illustrated in FIG. 1, the other has an inclination such that it tends to constantly bring the pin 60 back into this same position as soon as pressure ceases to be exerted on the pusher 6, the elongated opening allowing this rocker 59 to return to the rest position independently of the rocker 62.

This rocker 62 also carries a dowel 65 (FIG. 4) engaged in an opening 66 of a reset member 67 carrying three hammers 68, 69, 70. This dowel 65 serves to drive this reset member 67, as will be explained below. A positioning spring 71 of the pin 65 ends in two inclined planes, one of which tends to maintain the rocker 62 in the rest position, illustrated in FIG. 1, while the other tends to keep it in the position engaged in the column wheel 50, position corresponding to the resetting to zero and the locking of the indicator members of the chronograph counters by the hammers 68, 69, 70 in engagement with the cams 42, 34 and 43 respectively, as illustrated in phantom in the figure 4.

The reset member 67 has two elongated openings 72, 73 (fig. 1 and 4) whose longitudinal axes are parallel. The opening 72 is engaged with a bearing screw 74 which leaves this member free to move relative to this screw 74, while the opening 73 is engaged with a dowel 75. As a result, the member resetting to zero 67 can move rectilinearly in the longitudinal direction of the openings 72, 73, when it is driven by the rocker 62. It should also be noted that the hammer 69 comprises an adjustment system having an elongated opening 69a in which a guide pin 76 is engaged, while an eccentric 77 is used for fixing and adjusting the hammer 69. Thanks to this adjustment system, it is possible to guarantee the simultaneous contact of the hammers 68, 69, 70 with the shoulders of the three hearts 42, 34, 43 in the reset position illustrated in FIG. 4. As a variant, the hammer 69 could be mounted so elastic on the reset member which would have the same result.

In the position illustrated in solid lines in FIGS. 1 to 5, the chronograph mechanism is in operation. In this position, the clutch wheel 17 is engaged with the second chronograph wheel 18, while the retractable finger 27 meets the teeth of the first wheel 35 of the chronograph train once per revolution, that is to say say, once a minute, and spin it one step. Driven by the reference 37, the minute counter wheel 38 therefore also rotates one step, in the same direction as the wheel 35. Thanks to the reduction ratio due to the pinion 35 'to the wheel 40 and to the pinion 40 ', the wheel 41 of the hour counter also rotates in the same direction as the wheel 35, but by an angle 24 times smaller. Since the wheel of the minute counter 38 and that 41 of the hour counter are connected by a kinematic transmission, no offset can occur between them.

Between two drives of the train of the hour and minute counters by the retractable finger 27, the jumper 51 prevents this train from turning, thanks to the kinematic transmission existing between these two counters.

When the chronograph mechanism is to be stopped, pressure is exerted on the pusher 5 which rotates the ratchet wheel 52 by one step by means of the pawl 53. Consequently, the column wheel 50 rotates by the same angle , so that the finger 62a of the rocker 62 is unlocked. During this rotation, the finger 44b of the rocker 44 is moved into the position illustrated in thin lines by FIGS. 3 and 5. Thanks to the fingers 44a and 45a, this rocker 44 drives the rocker 45. These two rockers 44, 45 raise the 'clutch ring 33, so that the pinion 17' and the clutch disc 30 rotate while the axis 17a, the wheel 17 and the cam 34 stop rotating.

During the angular displacement of the lever 44, the pin 44c comes to bear against a rear face of the jumper 51, thus locking the train of the counter mechanism chronograph. It is possible that this gear train will stop when the retractable finger 27 drives this gear, so that, by the rotation of the gear 37, in the direction of the arrow F (fig. 5), the jumper 51 no longer presses on two teeth of this reference 37, but is raised, without the angle formed by the two inclined faces normally taking support on two teeth of this reference 37 having already passed on the other side of the tooth which raises. The ankle 44c, meeting the rear of the jumper 51 pushes it back to the bottom of the toothing of the reference 37 making it turn as well as all the wheels of the chronograph counters wheel back by an angle less than half a step from the wheel 35. The retractable finger 27 is therefore angularly displaced around its stud 28, thus arming the spring 26a. At the same time, the hand 39a of the minute counter is brought back in front of a scale on the dial. Thus, if the time measured corresponds to 9 minutes and 59 seconds for example, the hand 39a will be in front of the graduation 9 minutes and the second hand 19 in front of the graduation 59 seconds.

In this stop position two possibilities are offered. Either we reduce the counter to zero, or we measure a second time interval that we want to add to the previous one. In the latter case, the pusher 5 is pressed again, which rotates the ratchet wheel 52 and the column wheel 50 with one step. The rockers 44 and 45 are brought back to the position illustrated in solid lines in FIGS. 1 , 3 and 5, releasing the jumper 51, so that the spring 26a can disarm and the retractable finger 27 brings the train of the chronograph counter back to the angular position it occupied at the time of the previous stop, allowing the finger 27 to complete the training of this gear train interrupted by this stop.

During the next stop of the chronograph mechanism, one can for example choose to reset the three counters to zero by exerting pressure on push-piece 6. This first encounters strong resistance as long as the ankle 60 of the rocker 59 is on the first inclined plane of the spring 64 which makes an angle of the order of 75 ° with the direction of the force exerted by the pusher 6. When the ankle 60 arrives on the other inclined plane of this spring 64, the transmitted force suddenly becomes much higher. The finger 62a of the rocker 62 abruptly sinks into the column wheel 50 and the hammers 68, 69, 70 of the reset member 67 are forcefully applied against the cams 42, 34 and 43, bringing the three needles 39a, 19 and 39b at zero.

Given that the train of the chronograph counter mechanism is immobilized by the jumper 51 locked by the pin 44c of the rocker 44, the cams 42 and 43 integral with the axes 38a respectively 41a of the wheels 38 and 41 rotate with these axes and the hands 39a and 39b with respect to the wheels 38 and 41, frictionally connected to these axes 38a and 41a, immobilized by the jumper 51. As for the second chronograph wheel 18 and the clutch wheel 17, they can rotate since the ring clutch 33 is separated from clutch disc 30.

As soon as the pressure ceases to be exerted on the pusher 6 (fig. 1), the spring 64 pushes back the pin 60 and the rocker 59 independently of the rocker 62, thanks to the elongated opening 61 in which the pin 60 is engaged . The rocker 62 is kept engaged in the column wheel 50 by the spring 71 acting on the pin 65 until the start button 5 is actuated again. At this time, the column wheel pushes the rocker 62 backwards. At the same time the rockers 44 and 45, the column wheel 50 of which unlocks the finger 44b, are separated from the clutch ring 33 by the spring 48.

The foregoing description shows not only that a kinematic link exists between the indicator elements of the chronograph preventing any angular offset between them, but also that the number of mobiles forming this train of counters is reduced to a minimum. We have also seen that the clutch mobile is not only off-center which allows a significant gain of space in the center of the movement, but that this clutch mobile is a simple return with a 1/1 ratio between the seconds wheel 15 of the watch movement itself and the chronograph seconds wheel 18. As show in dashed lines the sections of Figures 2 and 3 this decentering of the clutch mechanism frees the center to allow the mounting of an oscillating weight OS for an automatic winding mechanism without increasing the height of the movement.

The small number of parts of the chronograph mechanism and the fact that all of this mechanism is on the same side of the movement allows maximum volume to be left for the vital organs, barrel and balance wheel. This low number of parts increases the reliability of the mechanism. It has also been found that the intermittent driving of the train of counters reduces the energy taken from the watch mechanism, thereby improving its chronometric performance.

Claims (6)

Timepiece with chronograph mechanism, comprising, - seconds, minutes and hours counters, having three respective indicator members (19, 39a, 39b) each secured to a rotary mobile (18, 38, 41), - clutch means (30, 32, 33) for selectively engaging these rotary mobiles (18, 38, 41) with a drive train (8, 14, 15) of this timepiece, a control device (50, 44, 45) for these clutch means (30, 32, 33) and - a reset mechanism (59-67) of these indicator members (19, 39a, 39b), characterized in that - a kinematic transmission (35, 37, 38, 35 ', 40, 40', 41) connects the mobile (38) secured to the indicator member (39a) of the minute counter to the mobile (41) secured to the member hour counter indicator (39b), - That the clutch means (30, 32, 33) comprise a mobile (17, 27) connected, on the one hand, kinematically to the mobile (18) secured to the indicator member (19) of the seconds counter , on the other hand, periodically at said kinematic transmission (35, 37, 38, 35 ', 40, 40', 41), and - in that an indexing member (51) is engaged with a mobile of the kinematic transmission (35, 37, 38, 35 ', 40, 40', 41). Timepiece according to claim 1, characterized in that said clutch means (30, 32, 33) comprise two mobiles (17 ', 17) mounted on a common axis (17a), a first of these mobiles ( 17 ') being free to rotate on this axis, while the second (17) is integral in rotation with this axis, that this first mobile (17') is integral with a first clutch member (30) while the second mobile (17) is integral in rotation with a second clutch member (33), axially displaceable and associated with elastic means (32) constantly tending to apply it axially against the first clutch member (30), one of these mobiles (17 ', 17) being engaged with a mobile integral with the seconds wheel (15) off center of the clockwork movement and has a gear ratio with it of 1/1, while the second of these mobile is engaged with the mobile (18) integral with the seconds indicator member in the center (19) of the chronograph counter and has a gear ratio with it of 1/1 and that the control device (50, 44, 45) of the clutch means (30 , 32, 33) includes a mechanism (44, 45) for axially displacing the second clutch member (33) against said elastic means (32). Timepiece according to claim 1, characterized in that it comprises a locking member (44c) of said indexing member (51) kinematically integral with said control device (50, 44, 45) of the clutch means , to lock this indexing member (51) with said kinematic transmission (35, 37, 38, 35 ', 40, 40', 41) in the disengaged position of said clutch means, and by the fact that a connection to friction is established between the respective rotary mobiles (38, 41) and the indicator members (39a, 39b) of the minute and hour counters. Timepiece according to claim 1, characterized in that the reset mechanism comprises a reset member (67), means (72-75) for guiding this member (67) along a rectilinear trajectory, this member comprising three reset elements (68-70) two of which (68, 70) are fixed relative to each other, while the third (69) is connected by elastic or adjusting means ( 69a) to said reset member (67). Timepiece according to claim 2, characterized in that it comprises in its center means for mounting an oscillating weight (OS) of an automatic winding mechanism. Timepiece according to claim 1, characterized in that said kinematic transmission (35, 37, 38, 35 ', 40, 40', 41) comprises five mobiles, a central mobile (35) periodically connected to said mobile (17 , 27) clutch means (30, 32, 33), this central mobile (35) being connected on the one hand, to the mobile (38) of the minute counter by an intermediate mobile (37), on the other hand , to the mobile (41) of the hour counter by another intermediate mobile (40, 40 ')

Images