CH716800A2 - Elastic needle clockwork display mechanism. - Google Patents

Abstract

The invention relates to a watch display mechanism with an elastic needle (1), which comprises a first drive barrel (2) integral with a first end of a flexible blade, and a second barrel (4) of the invention. 'drive integral with another end of the flexible blade. It has a display index (6) which, in an unstressed free state of the elastic needle (1) in which both said first barrel (2) and said second barrel (4) are not subjected to any stress. and are distant from each other, is distant from the first barrel (2) and from the second barrel (4), the service position of the elastic needle (1) being a constrained position where said first barrel (2) and said second barrel (4) are coaxial with each other about an output axis (D). The display mechanism (10) comprises first means for driving the first barrel (2) around the output axis (D), and second means for driving the second barrel (4) around the axis output (D), the first and second drive means being arranged to deform the flexible blade by varying the angular position of said second barrel (4) relative to the angular position of said first barrel (2) around said output axis ( D), and to vary the radial position of the display index (6) with respect to the output axis (D). The display mechanism comprises a differential mechanism acting on the drive train of the first gun (2) and on the drive train of the second gun (4) and the differential mechanism comprises at least a first satellite for the drive of the gun. first gun (2) and / or a second satellite for driving the second gun (4), and at least one input satellite carrier frame (180) driven in rotation by motor means for driving the elastic needle (1). The display mechanism also includes a torque regulator mechanism acting on said entry satellite carrier frame.

Description

Field of the invention

The invention relates to a variable geometry clock display mechanism, comprising at least one elastic hand which comprises a first drive barrel secured to a first end of a flexible blade, and a second barrel d 'drive integral with another end of said flexible blade, and comprising a display index which, in an unstressed free state of said elastic needle in which both said first barrel and said second barrel are not subjected to any stress and are distant from each other, is distant from said first barrel and said second barrel, the service position of said elastic needle being a constrained position where said first barrel and said second barrel are coaxial with each other around an output axis, said display mechanism comprising first means for driving said first barrel around said output axis, and second means for driving said second barrel around of said output axis, said first drive means and second drive means being arranged to deform said flexible blade, by varying the angular position of said second barrel relative to the angular position of said first barrel around said output axis, and to vary the radial position of said display index relative to said output axis.

The invention relates to a timepiece movement comprising at least one such display mechanism.

The invention relates to a watch comprising at least one such movement, and / or at least one such display mechanism.

The invention relates to the field of clockwork display mechanisms, and more particularly for timepieces with complications, the invention can be used equally well for static timepieces such as clocks or clocks, than for watches, because of the small dimensions of the mechanism according to the invention.

Background of the invention

[0005] Good visualization of the display members on a timepiece is important for the user.

[0006] The dials of many timepieces are not circular, and it is advantageous to have solutions which make it possible to occupy the entire available surface, for even better viewing.

[0007] The design of a variable geometry display mechanism makes it possible to break up a certain monotony of the displays, and to make the display more lively, with different aspects depending on the time of day, or according to particular time periods. For example, among a very large number of other possible applications, an AM / PM display can be provided simply by the shape of a needle, which has a first aspect during the twelve o'clock in the morning, and a second aspect during the remainder. of the day ; it is also possible to distinguish day / night displays, time zone displays, or the like.

[0008] Such a variable geometry display mechanism adds complexity to the timepiece, in particular a watch, and it is advantageous to limit its volume at the same time to allow its insertion into a small watch case. for example for a lady's watch, its complexity to limit the number of components and the cost of manufacture and assembly, and to regulate its consumption of torque in order to bring the least possible disturbance to the operation of the watch.

Summary of the invention

[0009] Elastic needles, and display mechanisms comprising such elastic needles, have been described in documents EP2863274, EP 3159751, EP3605244, and EP3605243, incorporated here by reference, and which disclose numerous variants.

The invention proposes to further simplify such an elastic needle display mechanism, and to make it even more compact and economical to produce, and to optimize its torque consumption.

The invention also proposes to prevent any bracing in this elastic needle display mechanism, by avoiding pushing a mobile, and by favoring mobile mounted dragging.

To this end, the invention relates to a variable geometry clock display mechanism, according to claim 1.

The invention relates to a timepiece movement comprising at least one such display mechanism.

The invention relates to a watch comprising at least one such movement, and / or at least one such display mechanism.

Brief description of the drawings

Other characteristics and advantages of the invention will become apparent on reading the detailed description which follows, with reference to the accompanying drawings, where: FIG. 1 schematically shows, partially, and in exploded perspective, an elastic needle display mechanism, limited to the barrels of the elastic needle which is not shown; this mechanism comprises a differential type mechanism carried by a planet carrier chassis, and the assembly thus represented constitutes an additional unit adaptable to an existing movement; the two barrels of the elastic needle are here coaxial around a roadway arranged to constitute an exit from such a movement; FIG. 2 is a partial diagrammatic representation, in assembled perspective, of the mechanism of FIG. 1, without the planet carrier plate; FIG. 3 schematically shows, partially and in side view, the mechanism of FIG. 2; FIG. 4 represents, schematically and in plan, an oval dial in front of which moves an elastic hand which such a display mechanism comprises, which hand is represented in two different positions: in solid lines at twelve o'clock, and in line interrupted at two o'clock; FIG. 5 schematically shows, partially, and in perspective, a display mechanism according to the invention, with the elastic needle on its barrels; FIG. 6 illustrates, similarly to FIG. 4, the associated ovoid trajectory of a top of the elastic needle; FIG. 7 illustrates, similarly to FIG. 4, the associated trajectory of a top of the elastic needle, which successively takes the shapes of almond and heart; FIGS. 8 and 9 represent, similarly to FIG. 4, the position of the differential plate and the positions of the arms of the elastic needle, respectively at noon in FIG. 8 and at four o'clock in FIG. 9; FIG. 10 is a block diagram of a timepiece comprising a movement and such a display mechanism; FIG. 11 is a partial diagrammatic representation, in assembled perspective, of a display mechanism according to the invention, comprising a torque regulating mechanism acting on a planet carrier frame; FIG. 12 schematically shows, in part and in top view, the mechanism of FIG. 11.

Detailed description of the preferred embodiments

[0016] The application EP3605244, relating to a variable geometry clock display mechanism with elastic hand, discloses a first actuation mechanism by means of mobiles with shaped teeth. Such an embodiment allows the execution of very innovative displays in watchmaking, and is however expensive, and reserved for luxury parts.

The same application also describes a second case of an actuating mechanism by means of a first differential on the cog of the first barrel and a second differential on the cog of the second barrel, and at least one cam constituting an input d 'such a differential. Therefore, it is necessary to find and size a suitable planetary gear (differential). Planetary gears have the advantage of achieving high transmission ratios in a small footprint. The input and output shafts are an extension of one another. There are many possibilities for combining gears. They make it possible, in particular, to produce interesting gearboxes. In the present case, it is a question of controlling one of the inputs of the differential, so as to generate an advance and respectively a delay of a specific equivalent value on each of the ends of the needle. And, when this value is zero, it is necessary to obtain a transmission ratio of 1 (the positive value means that the direction must also be the same).

The invention proposes to further simplify the mechanism and to make it even more compact and economical to produce. In particular, when it comes to implanting the elastic hand on a small caliber, such as a lady's watch, and in addition on the minute hand. The main difficulty is linked to the low torque available. It is therefore necessary to create a mechanism with the lowest possible energy consumption, and above all as regular as possible.

The invention relates to an elastic needle display mechanism. Such an elastic needle, and display mechanisms comprising such elastic hands, have been described in documents EP2863274, EP3159751, EP3605244, and EP3605243 incorporated here by reference, and which disclose numerous variants, in particular comprising one or more differential mechanisms. .

Optimizing the operation of such mechanisms requires smoothing of the actuating torque. The torque consumed by the system is relatively large, whether it is with one or two satellites. There is a consumption peak at the start of the rotation in the first 30 ° of the angular travel, then the torque decreases rapidly and becomes weaker, at a relatively low level, less than 20% of the maximum torque consumed during the peak, from a rotation angle of 120 ° and up to the end of the angular travel at 360 °. This has the effect of reducing the amplitude of the inertial mass of the resonator, in particular of the balance, which can alter the chronometry and the power reserve.

To this end, the invention relates more particularly to a clockwork display mechanism 10 with variable geometry, comprising at least one elastic hand 1.

This elastic needle 1 comprises a first drive barrel 2 integral with a first end of a flexible blade 3, and a second drive barrel 4 integral with another end of the flexible blade 3.

This flexible blade 3 can be a continuous blade, or a blade comprising a succession of segments 5 joined two by two at the vertices 6, as can be seen in FIGS. 5 and 6.

This flexible blade 3 comprises a display index which, in an unconstrained free state of the elastic needle 1 in which both the first barrel 2 and the second barrel 4 are not subjected to any constraint and are distant one from the other, is distant from the first barrel 2 and the second barrel 4, the service position of the elastic needle 1 being a constrained position where the first barrel 2 and the second barrel 4 are coaxial with each other. the other around an output axis D. In particular in a variant comprising segments 5 joined together, the display index is advantageously, but not necessarily, constituted by a vertex 6.

The display mechanism 10 comprises first drive means of the first barrel 2 around the output axis D, and second drive means of the second barrel 4 around the output axis D.

[0026] Variants where the first barrel 2 and the second barrel 4 are not coaxial are not described here, they remain achievable for certain special displays, in particular displays which are not of revolution, such as retrograde displays or the like.

The first drive means and the second drive means are arranged to deform the flexible blade 3, by varying the angular position of the second barrel 4 relative to the angular position of the first barrel 2 around the axis output D, and to vary the radial position of the display index relative to the output axis D. To improve operation and ensure the regularity of energy consumption, a good solution consists in equipping the mechanism display with elastic needle of a torque regulator, and in particular to be coupled in rotation, in particular around the output axis D, a regulating cam 801 with a differential planet carrier frame, in particular a planet gear carrier frame input 180. This cam 801 cooperates with an elastic arm 803, in particular but not limited to a prestressed spring. The track 802 of this regulation cam 801 comprises a rising edge and a continuous falling edge, and in particular has an ovoid profile.

Thus, according to the invention, the display mechanism comprises at least one differential type mechanism acting on the drive train of the first barrel 2 and on the drive train of the second barrel 4. And the differential mechanism comprises at least a first satellite 82 for driving the first gun 2 and / or a second satellite 84 for driving the second gun 4, and at least one input planet carrier frame 180 which is driven in rotation by motor means for driving the elastic needle 1, and this display mechanism comprises a torque regulating mechanism acting on the entry planet carrier frame 180.

More particularly, this torque regulating mechanism comprises, integral in rotation with the entry planet carrier frame 180, a regulating cam 801, the track 802 of which comprises a rising edge and a continuous falling edge. The torque regulating mechanism of the display mechanism comprises an elastic arm 803, a distal end of which, or a roller 804 carried by the distal end opposite to its recess 805, permanently cooperates with the track 802, the rising front of which lifts the elastic arm 803 and moves it away from the axis of rotation of the cam 801 to consume torque, and whose falling edge causes the elastic arm 803 to descend towards the axis of rotation of the cam 801 to restore torque to the system .

More particularly, the track 802 is symmetrical with respect to a plane passing through the axis of rotation of the entry planet carrier 180, and, more particularly still, the track 802 has an ovoid profile.

The distal end of the elastic arm 803, or a roller 804 carried by this distal end opposite the recess 805 of the elastic arm 803, permanently cooperates with the track 802 whose rising front lifts the elastic arm 803 and the 'moves away from the axis of rotation of the cam 801 which consumes torque, and the falling edge of which causes the elastic arm 803 to descend towards the axis of rotation of the cam 801, which restores torque to the system.

In the non-limiting example illustrated by the figures, between approximately 70 ° and 360 °, the regulating cam 801 raises the elastic arm 803, in particular at the level of the roller 804, and therefore consumes torque. Between 0 ° and 70 ° the elastic arm 803 descends on the side 802 of the cam 803 and supplies torque to the system. This results in a total system consumption curve which is much smoother, and with a lower maximum consumption. In the example illustrated, the torque varies between 0.3 times and 0.4 times the value of the maximum torque during the consumption peak of a mechanism not equipped with the invention.

This mechanism is comparable to the stackfreed of old watchmaking: the stackfreed is a system invented in the XVI <th> century, already cited by Leonardo da Vinci, for the regulation of the force of a mainspring, in particular a spring barrel, during its unwinding, and which comprises a leaf spring and an eccentric cam, to regulate the torque of the mainspring and improve the precision of a clock or a watch. It comprises a leaf spring which presses more or less strongly on the periphery of a cam carried by the barrel axis. We place the most prominent part of the cam so that the stackfreed creates a strong braking at the beginning of the unwinding and that this decreases as the spring relaxes in the barrel. It thus makes it possible to equalize the torque supplied by the spring over time, and thus improve the precision of time measurement.

[0034] The stackfreed comprises in particular an elastic cantilever arm, comprising a roller at its distal end opposite to its point of attachment. This roller presses on an eccentric cam track, in the shape of a snail. The cam is integral in rotation with a wheel, which is part of a cog driven by a shaft of the mainspring. This gear train is dimensioned so as to make the cam travel at most one revolution, during the period of unwinding of the mainspring. The force applied by the elastic arm against the cam exerts a braking torque on the mainspring, which reduces the latter's torque, which varies with the radius of the cam. When the mainspring is fully charged, the elastic arm rests on the largest radius of the cam, and the braking torque exerted is then maximum. When unwinding the mainspring, the cam pivots, the elastic arm is supported on increasingly small radii of the cam, which gradually reduces the braking torque, which compensates for the drop in torque generated by the mainspring . In a variant, the cam wheel comprises a stop face, to stop the unwinding of the mainspring at the end of a useful range where the torque delivered to the finishing gear is substantially constant.

The braking exerted by the stackfreed logically results in a loss of efficiency, which requires an oversizing of the mainspring, higher transmission ratios; its sizing is therefore difficult for its use in a watch, which led to its widespread abandonment as early as 1630, and its replacement by other mechanisms that consume less energy, such as the rocket mechanism.

However, the stackfreed mechanism is simple, and its major advantage is its smaller overall thickness than a rocket mechanism, its major drawback remains the necessary oversizing of the drive means and of the gear train to pass the torque safely.

The substitution of a continuous rising edge and falling edge cam, without breaking the profile by a threshold, unlike the snail cam of old mechanisms, allows the use of this new variant of the elastic arm stackfreed to ensure the torque regulation at the input of the display mechanism according to the invention.

Furthermore, by diverting the normal operation of a differential, it is possible to control the satellite. By implanting a feeler in the satellite, and by controlling the latter by a round cam, we obtain a speed ratio equal to one between the sun wheel and the supporting frame of the satellites: the assembly then behaves like a mobile.

Replacing the round cam of this example with a cam of suitable shape now makes it possible to control the advance or the delay that we wish to obtain on the barrel. It should be noted that here again, the mechanism does not have a return spring to keep the contact of the feeler on the cam, because it is the elastic needle which makes it possible to fulfill this function.

It is possible to avoid any arching phenomenon and avoiding the use of a mobile, in particular a satellite, pushed, by favoring the use of trailing mobiles.

A particular actuation of the needle consists in taking a differential planet gear carrier plate as a reference, so as to make each needle barrel work symmetrically. Figures 8 and 9 illustrate the angle of rotation to be imposed on guns 2 and 4 of needle 1. In Figure 8, needle 1 indicates noon: line A illustrates the position of the differential plate, which in this non-limiting example rotates at a rate of 1 revolution per hour, and lines B and C indicate the positions of the arms of hand 1. In figure 9, hand 1 indicates four o'clock, line A of the differential plate points the mark at four o'clock on the dial, and each arm B, C, relative to the planet carrier, has a symmetrical advance and retreat of the same angle Θ.

The display mechanism 10 then comprises a differential mechanism comprising an input satellite carrier frame 180 mounted to rotate freely about the output axis D. This input satellite carrier frame 180 comprises a first pivot 183 and a second pivot 181 respectively carrying a reference 103 and a single satellite 101 meshing with each other by their teeth 1039, 1019. This satellite 101 comprises an eccentric finger 1010, which is arranged to travel an internal track 105 d 'a fixed cam 104, and which is biased against this internal track 105 by the elasticity of the elastic needle 1 itself. This entry satellite carrier frame 180 comprises an input toothing 182, and a shaft 185 which carries, coaxial along the output axis D, a first carriageway 1020 comprising the first barrel 2 and a second carriageway 1040 comprising the second barrel 4, the teeth 1049 of one of which meshes with the teeth 1039 of the gearbox 103, and the teeth 1029 of the other mesh with the teeth 1019 of the satellite 101.

Thus, the construction is simplified by the use of a single cam which senses the information of the angular delta Θ to be applied. This information is transmitted directly to a first roadway 1020. A second roadway 1040 receives this information via a reference 103 which reverses the direction of the angular delta Θ to be applied, as visible in FIGS. 2 and 3: a single satellite 101, carried by the planet carrier plate 180 feels, on a single cam 105 which a flange 104 comprises, a single angular delta Θ to be applied to the two guns of the needle 1.

The satellite 101 applies the rotation directly to the first carriageway 1020 carrying the first gun 2. For the second carriageway, the satellite 101 transmits the rotation via the return 103 to the second carriageway 1040 carrying the second gun 4, in order to reverse the direction of rotation.

The satellite 101 carries a finger 1010 which feels the cam track 105.

The satellite carrier plate 180 here comprises a candle 185 for guiding the roadways 1040 and indirectly 1020, and an external toothing 182 driven by the clockwork movement, and pivots 181 and 183 for guiding the satellite 101 and the return 103. The toothing 1019 of the satellite 101 meshes, on the one hand with the toothing 1029 of the first carriageway 1020, and on the other hand with the toothing 1039 of the transmission 103, which meshes with the toothing 1049 of the second carriageway 1040.

Figure 3 shows that this mechanism is extremely compact, with a low thickness which allows it to be housed in a small watch case. The number of components is small, and none presents any particular complexity of realization, the cost of the assembly is therefore moderate.

The invention also relates to a timepiece movement 900 comprising at least one such display mechanism 10.

The invention also relates to a watch 1000 comprising at least one such movement 900, and / or at least one such display mechanism 10.

In short, the invention makes it possible to generate the advance and / or the delay on the two barrels of the elastic needle, making it possible to generate complex trajectories, all in a very simple, compact, little way. torque-hungry and therefore highly reliable.

This construction with a single satellite and a single cam has many advantages. The additional board is very simple. The single satellite is mounted trailing, and cannot butt in a clockwise direction. Energy consumption is low due to reduced friction. The loss of amplitude at the resonator is very low. The mechanism has few components, is not very bulky, and its assembly is easy.

Claims (7)

1. Variable geometry watch display mechanism (10), comprising at least one elastic hand (1) which comprises a first drive barrel (2) integral with a first end of a flexible blade (3) , and a second drive barrel (4) integral with another end of said flexible blade (3), and comprising a display index which, in an unstressed free state of said elastic needle (1) in which to both said first barrel (2) and said second barrel (4) are not subjected to any stress and are distant from each other, is distant from said first barrel (2) and from said second barrel (4), the position of service of said elastic needle (1) being a constrained position where said first barrel (2) and said second barrel (4) are coaxial with each other about an output axis (D), said mechanism d 'display (10) comprising first means for driving said first barrel (2) around said output axis (D), and second means driving said second barrel (4) around said output axis (D), said first driving means and second driving means being arranged to deform said flexible blade (3), by varying the angular position of said second barrel (4) relative to the angular position of said first barrel (2) around said output axis (D), and to vary the radial position of said display index relative to said output axis (D), characterized in that said display mechanism comprises at least one differential type mechanism acting on the drive train of the first barrel (2) and on the drive train of said second barrel (4) and in that said differential mechanism comprises at least one first satellite (82) for driving said first gun (2) and / or a second satellite (84) for driving said second gun (4), and at least one input satellite carrier frame (180) in rotation by motor means to drive it ment of said elastic needle (1), and in that said display mechanism comprises a torque regulating mechanism acting on said input planet carrier frame (180). 2. Display mechanism (10) according to claim 1, characterized in that said torque regulating mechanism comprises, integral in rotation with said input planet carrier frame (180), a regulating cam (801) whose track (802) comprises a rising edge and a continuous falling edge, in that said torque regulating mechanism comprises an elastic arm (803), including a distal end, or a roller (804) carried by said distal end opposite to its embedding ( 805), cooperates permanently with said track (802), the rising edge of which lifts said elastic arm (803) and moves it away from the axis of rotation of said cam (801) in order to consume torque, and of which the falling edge causes said elastic arm (803) to descend towards the axis of rotation of said cam (801) to restore torque to the system. 3. Display mechanism (10) according to claim 1 or 2, characterized in that said track (802) is symmetrical with respect to a plane passing through said output axis (D) of the input planet carrier 180. 4. Display mechanism (10) according to claim 3, characterized in that said track (802) has an ovoid profile. 5. Display mechanism (10) according to one of claims 1 to 4, characterized in that said input satellite carrier frame (180) is mounted to rotate freely about said output axis (D), and comprises a first pivot (183) and a second pivot (181) respectively carrying a return (103) and a planet gear (101) meshing with each other by their teeth (1039; 1019), said planet gear (101) comprising a eccentric finger (1010), which is arranged to travel an internal track (105) of a fixed cam (104), and which is biased against said internal track (105) by the elasticity of said elastic needle (1), said input planet carrier frame (180) comprising an input toothing (182), and a shaft (185) which carries, coaxial along said output axis (D), a first carriageway (1020) comprising said first barrel ( 2) and a second carriageway (1040) comprising said second barrel (4), of which the teeth (1049) of one mesh with the teeth (1039) of said reference (103), and of which the toothing (1029) of the other meshes with the toothing (1019) of said satellite (101). 6. Timepiece movement (900) comprising at least one display mechanism (10) according to one of claims 1 to 5. 7. Watch (1000) comprising at least one movement (900) according to claim 6, and / or at least one display mechanism (10) according to one of claims 1 to 5.