CH715546A2 - Display mechanism for a watch movement. - Google Patents

Abstract

The present invention relates to a display mechanism for a watch movement, comprising first and second display mobiles (2, 4), coaxial, with first and second information, a kinematic connection between the first and second mobiles display (2, 4) arranged such that the first display mobile (4) has a rotation period k times greater than that of the second display mobile (2), the kinematic link comprising a satellite (8 ) carried by the second display mobile (2) and arranged in engagement, on the one hand, with a toothing of the first display mobile (4) and, on the other hand, with a coaxial reference toothing (10) to the first display mobile (4) and having a pitch diameter substantially equal to that of the teeth of the first display mobile (4), as well as a number of teeth differing by at least one tooth with reference to the number of teeth of the teeth of the first display mobile (4).

Description

Technical area

The present invention relates to a display mechanism for a watch movement, comprising a first display mobile, mobile in rotation along an axis of rotation X1 to allow the display of a first item of information in association with a first display member, a second display mobile coaxial with the first display mobile and intended to allow the display of second information in association with a second display member, a kinematic link between the first and second display mobiles arranged so that the first display mobile has a rotation period k times greater than that of the second display mobile.

The present invention also relates to a timepiece movement comprising such a timepiece mechanism as well as a timepiece comprising at least one such timepiece movement.

State of the art

Such display mechanisms are well known from the state of the art, in particular for producing the display of the current time. Indeed, typically, a watch movement comprises a floor driven from a gear train and intended to carry a hand indicating the current minutes, while an hour wheel is arranged coaxially with reference to the floor to wear a hand indicating the current hours. A kinematic connection is then implemented between the roadway and the hour wheel in the form of a timer mobile comprising two toothed boards integral and coaxial, one of which is engaged with the roadway and the other with the wheel of the hours to drive the hour wheel with a rotation period twelve times greater than that of the road, that is to say to achieve a reduction.

These constructions have been perfectly mastered for a very long time and their implementation in a conventional watch movement is carried out without there being any need to ask any questions, either in relation to their merits or even in relation with how to proceed to achieve them concretely.

Thus, although no change in the above approach seems necessary, the Applicant has sought to develop an alternative construction to replace the conventional reduction cogs, of the timer type, in watchmaking display mechanisms.

Disclosure of invention

A main object of the present invention is to provide an alternative construction to the constructions already known for connecting together, with a reduction, display mobiles in a display mechanism for a watch movement.

To this end, the present invention relates more particularly to a display mechanism of the type mentioned above, characterized in that the kinematic link comprises at least one toothed satellite mounted free in rotation on the second display mobile, along an axis of rotation X2 distant from the axis of rotation X1, and arranged in engagement, on the one hand, with a toothing of the first display mobile and, on the other hand, with a reference toothing coaxial with the first mobile display and presenting a pitch diameter substantially equal to that of the teeth of the first display mobile, as well as a number of teeth differing by at least one tooth with reference to the number of teeth of the teeth of the first display mobile.

Thanks to these characteristics, an alternative construction display mechanism is obtained with reference to the known mechanisms making it possible to apply a significant reduction ratio in return for a limited space requirement. In addition, considering for example the case of the conventional timer, the construction according to the present invention makes it possible to reduce the number of holes to be made in the frame elements.

[0009] Preferably, the number of teeth of the reference toothing has a difference of between 1 and 20%, preferably between 1 and 10%, with reference to the number of teeth of the toothing of the first display mobile.

As long as the difference between these numbers of teeth remains within a limited range, the teeth can be conventional and produced without having to take any particular measure.

Advantageously, when the information to be displayed is the current hour and the current minute, the first and second display mobiles are respectively an hour wheel and a floor or are respectively secured to an hour wheel and of a carriageway, the reference toothing has a number of teeth slightly less than the number of teeth of the first display mobile, such that k is equal to twelve.

With a lower number of teeth for the reference toothing relative to the first display mobile, the satellite pushes the first display mobile to rotate it in the same direction as the second display mobile.

According to a preferred embodiment, one can provide that the display mechanism comprises a support intended to be rotatably mounted on a frame of a watch movement and carrying the first and second display mobiles as well as the kinematic connection .

The present invention also relates to a timepiece movement comprising a display mechanism meeting the characteristics which have just been stated as well as a driving mobile arranged to rotate one of the first and second display mobile. .

According to a preferred embodiment, when the display mechanism comprises a support, it can be provided that it also includes a source of energy intended to drive in rotation a driving mobile having the same axis of rotation as the support and arranged to rotate one of the first and second display mobiles.

One can advantageously provide that the frame carries a drive member capable of driving the support in rotation, either in a trailing manner, or by jumps.

In general, when the first and second display mobiles are an hour wheel and a carriageway respectively, it is possible to provide that the watch movement includes a kinematic connection between the drive mobile and the carriageway arranged in such a way that the angular orientation of the roadway is independent of the angular orientation of the support with reference to the frame.

In addition, one can also provide that the support carries a return arranged in engagement with a fixed toothing and having a kinematic connection with the reference toothing of the display mechanism, the corresponding gear ratios being such as the toothing of reference has an angular orientation independent of that of the support with reference to the frame. By way of examples, the fixed toothing may be an external toothing formed on a wheel in the center or an internal toothing provided on a peripheral crown.

In general, the present invention also relates to a timepiece comprising a timepiece movement meeting the characteristics set out above.

Brief description of the drawings

Other characteristics and advantages of the present invention will appear more clearly on reading the detailed description of preferred embodiments which follows, made with reference to the accompanying drawings given by way of non-limiting example and in which:

- Figure 1 shows a diagram illustrating the basic principle of a display mechanism according to a first preferred embodiment of the present invention;

- Figure 2 shows a simplified front view of an embodiment of a display mechanism according to the operating principle illustrated in Figure 1;

- Figure 3 shows a diagram illustrating the basic principle of a display mechanism according to a second preferred embodiment of the present invention;

- Figure 4 shows a simplified front view of an exemplary embodiment of a display mechanism according to the operating principle illustrated in Figure 3;

- Figure 5 shows a simplified sectional view of part of a timepiece movement comprising a display mechanism according to Figure 4, the section being taken along the line V-V of Figure 4, and

- Figure 6 shows an exploded and simplified perspective view of part of the watch movement illustrated in Figure 5.

Mode (s) of Carrying Out the Invention

Figure 1 shows a diagram illustrating the basic principle of a display mechanism according to a first preferred embodiment of the present invention.

In general, the display mechanisms which will be described below are applied to the display of the current time, more precisely of the current hours and minutes, by way of nonlimiting illustration. Information of different natures may be displayed by implementing the mechanisms described without departing from the scope of the present invention. Furthermore, the present invention can be equally applied in relation to a mechanical watch or to an electromechanical watch.

FIG. 1 illustrates by way of example how a carriageway 2 and an hour wheel 4, coaxial along an axis of rotation X1, can be kinematically connected to one another other than by means of a timer.

The pavement 2 here has a toothed board 6 of larger diameter than on a conventional pavement. This plate 6 thus carries a satellite 8 free to rotate on the roadway 2 along an axis of rotation X2 distant from the axis of rotation X1.

The satellite 8 has a sufficient thickness to be able to mesh, on the one hand, with the toothing of the hour wheel 4 and, on the other hand, with a reference toothing 10 which is fixed here.

The principle of implementation of the invention lies in the fact that the reference toothing 10 has geometrical characteristics close to but different from those of the hour wheel 4. It is preferable to provide that the reference toothing 10 has a pitch diameter roughly equal to that of the toothing of the hour wheel 4, but a slightly different number of teeth. Thus, the satellite 8 driven in rotation by the movement of the roadway 2 rolls on the reference toothing 10. In doing so, it acts on the toothing of the hour wheel 4 to rotate the latter.

2 shows a simplified front view of an embodiment of a display mechanism according to the operating principle which has just been described.

This display mechanism is intended to be implemented in a watch movement, preferably by providing that a driving mobile, itself driven from a gear train, is arranged in engagement with the floor 2 to train it in rotation at the rate of one complete revolution per hour.

The hour wheel 4 here has a number of teeth less than the number of teeth of the reference toothing 10 so that, when the satellite 8 moves in the direction of clockwise rotation, it tends to push the wheel of the 4 hours to also rotate it clockwise.

The principle of operation of this construction allows to introduce, between the floor 2 and the hour wheel 4, a reduction of ratio k whose value is equal to Zh / (Zh-Zr), where Zh is the number of teeth of the hour wheel 4 and Zr the number of teeth of the reference toothing 10. In the construction example illustrated in FIG. 2, Zh is equal to 24 and Zr is equal to 22, which gives a value of 12 for k and corresponds to the classic ratio introduced by the timer.

This construction therefore advantageously allows to implement a kinematic connection introducing an appropriate reduction, possibly significant, between two display mobiles, without the need to drill holes in the frame as is particularly the case when using a timer type reduction.

The reference toothing 10 may for example be secured to a plate, a bridge or a dial in the corresponding timepiece.

It should be noted that such a construction can also be used to ensure the introduction of a reduction ratio between two display mobiles rotating in opposite directions as a function of that of the two teeth which has the greatest number teeth.

Figure 3 shows a diagram illustrating the basic principle of a display mechanism according to a second preferred embodiment of the present invention.

The reference numerals used so far will be repeated in the following description to designate equivalent or identical components.

The operating principle of this second preferred embodiment is similar to that of the first embodiment and is distinguished from the latter by the fact that the reference toothing 10 is no longer fixed but carried by a rotary support ( reference numeral 20 in FIGS. 4 to 6), the latter carrying the carriageway 2 and the hour wheel 4 to display the current time on a rotary dial.

FIG. 4 represents a simplified front view of an exemplary embodiment of a display mechanism in accordance with the operating principle which has just been described, while FIGS. 5 and 6 represent other views, respectively in section along line VV of FIG. 4 and in exploded perspective, of this display mechanism.

The display mechanism comprises a support 20 intended to be assembled on a timepiece movement frame element, typically a plate, so as to be able to rotate with reference to the frame. The support 20 can for example be assembled to the plate by a ball bearing or any other known suitable means.

All the components carried by the support 20 are not illustrated, for the sake of simplification, provided that they do not directly influence the implementation of the invention.

The kinematic connection between the floor 2 and the hour wheel 4 is performed in the same manner as in the first embodiment, that is to say that the floor 2 carries a satellite 8 arranged in engagement with the times with the toothing of the hour wheel 4 and with a reference toothing 10. The reference toothing 10 is no longer fixed from an absolute point of view here but remains fixed with reference to the display of the current time .

More specifically, the support 20 also carries a dial 22 for displaying the current time, the latter being integral with the reference toothing 10.

The floor 2 is arranged in engagement with a reference 24, carried by the support 20, the reference 24 itself being arranged in permanent engagement with a central drive mobile 26 secured to a floor of the basic watch movement (not shown). Consequently, the rotation of the central drive mobile 26 acts on the gear 24 to make it rotate, which causes the rotation of the roadway 2 about its axis of rotation X1.

As an illustrative and non-limiting example, the teeth of the floor 2 and the central drive mobile 26 are identical here. Thus, the pavement 2 makes a complete turn on itself in one hour, like the central training mobile 26.

This gives a kinematic connection, between the central drive mobile 26 and the floor 2, arranged in such a way that the angular orientation of the floor 2, for an observer, is independent of the angular orientation of the support. 20 with reference to the structure of the watch movement.

A compensation mechanism is then provided to keep the angular orientation of the dial 22 fixed by compensating for the rotation of the support 20. This compensation mechanism comprises a peripheral ring gear 28, integral with a frame element of the watch movement and with which meshes a first pinion of a stepped gear 30 mounted to rotate freely on the support 20. The stepped gear 30 comprises a second gear arranged in engagement with a compensating toothing 32 integral with the dial 22.

The gear ratios in play are preferably chosen here so that the dial 22 has a fixed angular orientation for an observer, in other words relative to the case of the corresponding timepiece.

The reference toothing 10 being integral with the dial 22 and therefore the compensation teeth 32, it also benefits from the effects produced by the compensation mechanism which it retransmits to the hour wheel 4, by means of two satellites 8 as visible in FIGS. 5 and 6 (the second satellite not being shown in FIG. 4). Thus, the hour wheel 4 undergoes combined actions, on the one hand, from the satellite 8 and, on the other hand, from the compensation mechanism. It will be noted that, by virtue of the compensation mechanism, the reference toothing 10 and the dial 22 have respective angular orientations independent of that of the support 20.

Alternatively, it is possible to provide that the compensation mechanism comprises a central fixed toothing in place of the peripheral ring gear 28, without departing from the scope of the present invention.

As regards the support 20, it can be rotated by any suitable means of the watch movement, in a trailing manner or by jumps.

As with the first embodiment, a construction is obtained here which makes it possible to define a reduction, possibly significant, between two display mobiles without the need to make other holes in the frame than those necessary the pivoting of the two display mobiles.

The above description attempts to describe two particular embodiments by way of nonlimiting illustration and, the invention is not limited to the implementation of certain particular characteristics which have just been described, such as for example the nature of the information that the first and second display mobiles are intended to display or also the gear ratios specifically mentioned. Furthermore, it can also be provided, from the second embodiment, that the watch movement includes a specific drive mechanism for the support, dragging or jumping and possibly including a specific energy source, without going beyond the ambit of the invention.

The embodiments which have been described allow the person skilled in the art to produce a wide variety of constructions of display mechanisms, of the type comprising two display mobiles connected to each other by a link. kinematics introducing a reduction and requiring no specific drilling in a frame element, according to its own needs and without departing from the scope of the present invention.

Claims (11)

1. Display mechanism for a watch movement, comprising a first display mobile (4), mobile in rotation along an axis of rotation X1 to allow the display of a first item of information in association with a first display member, a second display mobile (2) coaxial with said first display mobile (4) and intended to allow the display of second information in association with a second display member, a kinematic link between said first and second display mobiles (2, 4) arranged such that said first display mobile (4) has a period of rotation k times greater than that of said second display mobile (2) , characterized in that said kinematic link comprises at least one toothed satellite (8) mounted free in rotation on said second display mobile (2), along an axis of rotation X2 distant from said axis of rotation X1, and arranged in engagement, d on the one hand, with a toothing of said first display mobile (4) and, on the other hand, with a reference toothing (10) coaxial with said first display mobile (4) and having a pitch diameter substantially equal to that of the teeth of said first display mobile (4), as well as a number of teeth differing by at least one tooth with reference to the number of teeth of the toothing of said first display mobile (4). 2. Mechanism according to claim 1, characterized in that the number of teeth of said reference toothing (10) has a difference of between 1 and 20%, preferably between 1 and 10%, with reference to the number of teeth of the toothing of said first display mobile (4). 3. Mechanism according to claim 1 or 2, when said information to be displayed is the current hour and the current minute, said first and second display mobiles being respectively an hour wheel (4) and a roadway (2) or being respectively secured to an hour wheel (4) and a roadway (2), characterized in that said reference toothing (10) has a number of teeth slightly less than the number of teeth of said first display mobile (4 ), such that k is equal to twelve. 4. Mechanism according to one of the preceding claims, characterized in that it comprises a support (20) intended to be rotatably mounted on a frame of a watch movement and carrying said first and second display mobiles (2, 4 ) as well as said kinematic link. 5. Watch movement comprising a frame carrying a display mechanism according to one of claims 1 to 3 as well as a drive mobile arranged to drive in rotation one of said first and second display mobiles (2, 4 ). 6. Watch movement comprising a bearing frame a display mechanism according to claim 4, and an energy source intended to drive in rotation a driving mobile (26) having the same axis of rotation as said support (20) and arranged to drive in rotation one of said first and second display mobile (2, 4). 7. Watch movement according to claim 6, characterized in that said frame carries a drive member capable of driving said support (20) in rotation. 8. Watch movement according to claim 6 or 7, when said first and second display mobiles are respectively an hour wheel (4) and a roadway (2), characterized in that it comprises a kinematic connection between said mobile d drive (26) and said roadway (2) arranged such that the angular orientation of said roadway (2) is independent of the angular orientation of said support (20) with reference to said frame. 9. Watch movement according to claim 8, characterized in that said support (20) further carries a reference (30) arranged in engagement with a fixed toothing (28) and having a kinematic connection (32) with said reference toothing ( 10) of the display mechanism, the corresponding gear ratios being such that said reference toothing (10) has an angular orientation independent of the angular orientation of said support (20) with reference to said frame. 10. Timepiece comprising a timepiece movement according to one of claims 5 to 9. 11. Timepiece comprising a timepiece movement according to claim 9, characterized in that it comprises a dial (22) integral with said reference toothing (10) of the display mechanism.