TIMEPIECE MOVEMENT INCLUDING AN ANALOGUE DISPLAY

Abstract

The timepiece movement is provided with an analogue display device for an item of information whose value varies periodically or intermittently, this analogue display device including an indicator for said information provided with a toothing and a mechanism for the periodic or intermittent driving of the indicator, this mechanism comprising a rotating wheel set whose pinion, in a meshing relationship with the toothing, is formed of two pins which are diametrically opposite relative to the rotational axis of the rotating wheel set, these two pins being configured to alternately penetrate successive hollows in the toothing and to form a self-locking system when the timepiece movement is subjected to shocks. Each of the two pins has, in a general plane of the toothing perpendicular to the axis of rotation of the rotating wheel set, a transverse profile having a first outer portion substantially in the arc of a circle centred on the axis of rotation.

Claims

1. A timepiece movement provided with an analogue display device for an item of information whose value varies periodically or intermittently, said analogue display device including an indicator for said information provided with a toothing and a mechanism for the periodic or intermittent driving of the indicator, said mechanism comprising a rotating wheel set whose pinion, in a meshing relationship with said toothing, is formed of two pins which are diametrically opposite relative to the rotational axis of the rotating wheel set, these two pins being configured to alternately penetrate successive hollows in said toothing and to form a self-locking system when the timepiece movement is subjected to shocks, at least when the pinion is in either of the two tangential positions where the two pins are oriented substantially tangentially to the indicator toothing, each of the two pins having, in a general plane of said toothing perpendicular to the axis of rotation of the rotating wheel set, a transverse profile having a first outer portion substantially in the arc of a circle centred on the axis of rotation, the two pins of said pinion being configured with respect to said indicator toothing such that there is a dead angle for the driving of said indicator by said pinion in at least one direction of rotation from each of said two tangential positions of the pinion, said rotating wheel set thus does not drive the indicator in two dead angle zones defined inside an angular marker connected to the timepiece movement and centred on the axis of rotation of the rotating wheel set, said two dead angle zones including at least said dead angle respectively from the two tangential positions of the pinion, the first outer portion of the transverse profile of the two pins extending over an angular distance substantially equal to or greater than said dead angle.

2. The timepiece movement according to claim 1, wherein said dead angle is substantially equal to or greater than fifteen degrees.

3. The timepiece movement according to claim 1, wherein said dead angle is substantially equal to or greater than twenty-five degrees.

4. The timepiece movement according to claim 2, wherein the first outer portion of the transverse profile of the two pins extends over an angular distance comprised between 3/2 multiplied by said dead angle and substantially two times said dead angle.

5. The timepiece movement according to claim 4, wherein each hollow of said toothing has an opening, at the ends of two adjacent teeth, having a dimension smaller than the width of said hollow in the region of contact thereof with the two pins during the driving of said indicator by the rotating wheel set.

6. The timepiece movement according to claim 5, wherein each pin has a radial dimension relative to the axis of rotation of said rotating wheel set and a tangential dimension, perpendicular to the radial dimension, whose value is substantially equal to two times that of the radial dimension or greater.

7. The timepiece movement according to claim 2, wherein said item of information is a first item of information, said analogue display is a first analogue display and said indicator is a first indicator, wherein said timepiece movement includes a second analogue display including a second indicator kinematically connected to said mechanism driving the first indicator, said second display being arranged such that the second indicator is driven by the drive mechanism to indicate a second item of information, while the rotating wheel set remains in one or other of the two dead angle zones.

8. The timepiece movement according to claim 7, wherein, in the event of a shock, the two pins of said pinion lock said first indicator when the rotating wheel set is angularly within either of the two dead angle zones.

9. The timepiece movement according to claim 7, wherein the second analogue display and its drive mechanism are arranged such that the second indicator can make a rotation of at least 360 while said pinion is subjected to a rotation inside said dead angle from either of its two tangential positions.

10. The timepiece movement according to claim 9, wherein the second analogue display is a display of a measured time interval.

11. The timepiece movement according to claim 1, wherein said indicator, respectively the first indicator, is a date ring.

12. The timepiece movement according to claim 1, wherein said pinion and said toothing are arranged such that, when the pinion is in either of its two tangential positions, said indicator, respectively said first indicator, has an angular play that is smaller than or substantially equal to thirty-five microns.

13. The timepiece movement according to claim 1, wherein said pinion and said toothing are arranged such that, when the rotating wheel set is subjected to a rotation over all of either one of the two dead angle zones, said indicator, respectively said first indicator, has an angular play that remains smaller than or substantially equal to forty microns.

14. The timepiece movement according to claim 1, wherein said drive mechanism includes a drive source which is formed by a bidirectional electrical motor controlled by an electronic unit.

15. The timepiece movement according to claim 7, wherein said indicator, respectively the first indicator, is a date ring.

16. The timepiece movement according to claim 7, wherein said pinion and said toothing are arranged such that, when the pinion is in either of its two tangential positions, said indicator, respectively said first indicator, has an angular play that is smaller than or substantially equal to thirty-five microns.

17. The timepiece movement according to claim 7, wherein said pinion and said toothing are arranged such that, when the rotating wheel set is subjected to a rotation over all of either one of the two dead angle zones, said indicator, respectively said first indicator, has an angular play that remains smaller than or substantially equal to forty microns.

18. The timepiece movement according to claim 7, wherein said drive mechanism includes a drive source which is formed by a bidirectional electrical motor controlled by an electronic unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention will be described below with reference to the annexed drawings, given by way of non-limiting example, and in which:

[0016] FIG. 1 represents an electromechanical movement, of the type of a main embodiment of the present invention, which implements a known pinion-pin for actuation of a date disc.

[0017] FIG. 2 is an enlarged partial view of FIG. 1.

[0018] FIG. 3 shows a variant of the movement of FIG. 1 on the basis of which the issue at the heart of the present invention is explained in more detail.

[0019] FIGS. 4A and 4B are partial views of a first embodiment of the invention.

[0020] FIG. 5 is a partial top view of a second embodiment of the invention.

[0021] FIG. 6 is a sophisticated variant of the second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0022] Referring to FIGS. 1 and 2, there is described below an electromechanical movement 2 of the type of a main embodiment of the invention with the driving of a date ring via a known pin-pinion. This timepiece movement 2 includes a first display formed by a date ring 4 comprising an inner toothing 5, this ring being periodically driven (normally once per day) by a drive mechanism 8 which includes a rotating wheel set 10 whose pinion 12 meshes with toothing 5. This drive mechanism is actuated by a drive source which is formed by a bidirectional electrical motor 16 controlled by an electronic unit, in particular of the stepping type. Pinion 12 is formed of two pins 22 and 23 which, during the driving of ring 4, alternately penetrate successive hollows 7 in toothing 5. Pin-pinion 12 is characterized in that it forms with toothing 5, when the timepiece movement is subjected to shocks, a self-locking system for the date ring at least when the pinion is in either of the two tangential positions where the two pins are oriented substantially tangentially to circular toothing 5 (parallel to direction T).

[0023] To hold the date ring in a plurality of distinct positions in which it remains stationary during successive date display periods, a positioning jumper spring 14 is provided. This jumper spring is arranged to be stably inserted between two adjacent teeth of the toothing in each of the plurality of distinct positions of ring 4. This jumper spring is preferably sized to ensure precise positioning of ring 4, given the considerable play between the two pins 22, 23 and toothing 5 and also the relatively large dead angle a for pinion 12 on its rotation from its two tangential positions. However, the jumper spring is not provided here for an anti-shock function so that the elastic constant can be lower than in conventional devices.

[0024] Timepiece movement 2 further includes a second indicator 18 kinematically connected to mechanism 8 driving first indicator 4, this second display being arranged such that second indicator 18 can be driven by this drive mechanism to indicate a second item of information, in particular relating to a measured time interval, while rotating wheel set 10 remains in one or other of the two dead angle zones for driving the first indicator. Indeed, the two pins of pinion 12 are configured with respect to date ring toothing 5 such that there is a dead angle for driving the indicator by the pinion in at least one direction of rotation from each of the two tangential positions of the pinion; the rotating wheel set thus does not drive the date ring in two dead angle zones defined within an angular marker connected to the timepiece movement and centred on the axis of rotation A10 of the rotating wheel set, these two dead angle zones comprising at least the dead angle indicated respectively from the two tangential positions of the pinion. As represented in FIG. 2, where pinion 12 is in an angular position located at the end of a dead angle zone, the second analogue display and its drive mechanism, which is formed here by part of the wheel sets of drive mechanism 8, are arranged such that second indicator 18 can make a rotation of at least 360 while the pinion is subjected to a rotation inside dead angle a from one of its two tangential positions. During actuation of indicator 18, there is a reset or periodic backward return of the indicator while the pinion remains angularly inside a dead angle zone. Two items of information can thus be displayed independently with a single drive mechanism and, in particular, a single electrical motor 16.

[0025] Timepiece movement 2 has several advantages, particularly in relation to the driving of two indicators supplying independent items of information (date and measured time interval) by means of the same single drive source and with the anti-shock function obtained via a relatively simple, inexpensive system that is easy to mount inside the timepiece movement. However, this timepiece movement has some drawbacks. Firstly, the pins are relatively small. There is therefore a real risk of them being damaged when the timepiece movement is subjected to a shock, especially of them being permanently deformed by bending under the force exerted by the toothing on the pins during some shocks. Of course, the cross-section of the pins can be slightly increased, but this then reduces the dead angle zones. It is also possible to take a known toothing with hollows having parallel sides, as represented in FIG. 3, to increase the dead angle zones. However, even in that case, a positioning jumper is provided, which is cumbersome and requires a certain amount of energy on a change of date. Further, the anti-shock function loses efficiency when pinion 12 is located in the end region of a dead angle zone, so that in case of shocks in such a situation, it is not possible to ensure sufficient locking of the date ring.

[0026] FIG. 3 represents a variant of timepiece movement 2 wherein various parameters have been improved, starting from a similar configuration to that known in the prior art. Only pin-pinion 12A of the drive mechanism of timepiece movement 2A is represented, since the other parts are identical to those of timepiece movement 2. Pinion 12A includes two cylindrical pins 24 and 25 with a diameter D. The hollows 7A of toothing 5A of date ring 4A have a substantially rectangular profile and thus parallel sides (side walls). The width L of the hollows is approximately equal to the width of the teeth at mid-height. Diameter D of the pins is greater than half the width L of hollows 7A to ensure sufficient mechanical strength.

[0027] To obtain a maximum dead angle for such a configuration, in the two aforementioned tangential positions, the pins are arranged to leave a relatively small play between the pins and the two teeth defining the outer sides 28 and 29 of two respective hollows facing the two pins, so that the date ring has a relatively small angular play when the pinion is in one or other of the two tangential positions. Thus, with the best adjustment of the dimensions of toothing 5A and of the pins, it would be possible to do without a positioning jumper in these two tangential positions, which is one of the objects of the invention. However, as can be seen in FIG. 3, when pinion 12A rotates in a dead angle zone, for example during the actuation of a second indicator, the angular play increases and as soon as the exiting pin is no longer in mesh with the toothing, this play becomes significant with a value E1 equal to the difference between width L of the hollows and the diameter of the pins. It is not therefore possible to do without a positioning jumper in movement 2A.

[0028] It will be noted that the pinion is generally arranged to be in one of its two tangential positions in the rest periods when neither the date ring nor the second indicator are driven. These rest positions are preferred since they ensure the best anti-shock protection. It will be noted that the locking torque exerted by the pinion immediately diminishes moving away from said rest positions. Finally, it will be noted that the preferred rest positions are not always those that occur in practice for various reasons; the first arising from the fact that pinion 12A can be initially mounted with an angular position having a certain variation, and the second from the fact that the motor may miss some steps so that the precise angular position of the pinion is not known. Consequently, even when the drive mechanism is inactive in rest periods, the positioning jumper provided in the prior art is required in order to overcome this problem. However, the invention efficiently overcomes these problems by proposing the solution that will be explained below.

[0029] Referring to FIGS. 4A and 4B, a first embodiment of a timepiece movement 30 will be described. With the exception of pinion 32, the drive mechanism for date ring 4A and the latter are identical to those implemented in movement 2A of FIG. 3. They will not, therefore, be described again here. Pinion 32 includes two pins 34 and 36 which each have, in a general plane of toothing 5A perpendicular to axis of rotation A10 of the rotating wheel set including pinion 32, a transverse profile having a first outer portion 38 substantially in the arc of a circle, centred on the axis of rotation. The rear portion 40 of each pin is rounded and substantially corresponds to the rear portion of pins 24 and 25 of FIG. 3. Consequently, in the example represented, a circle having the diameter of pins 24 and 25 is inscribed within each pin 36, 38. These pins 36 and 38 are symmetrical relative to a plane comprising axis of rotation A10 and have the same behaviour regardless of the direction of rotation of pinion 32. The tangential length T of these pins, perpendicular to said plane of symmetry, is arranged to be greater than diameter D of pins 24, 25 and than radial dimension R of pins 36, 38. The outer, arc of a circle portion advantageously extends over the entire tangential length. It will be noted that, in order to drive ring 4A, tangential length T is smaller than the width L of hollows 7A.

[0030] In FIG. 4B, pinion 32 has been rotated by dead angle ; the date ring has remained in the same angular position during this rotation. It is observed firstly that the dead angle is substantially equal to that featured in the embodiment of FIG. 3. Generally speaking, the dead angle is arranged to be substantially equal to or greater than fifteen degrees (15=<). It will be noted that in a preferred variant, the dead angle is substantially equal to or greater than twenty-five degrees (25=<). Next, it is observed that the outer arc of a circle of the transverse profile of the two pins extends over an angular distance which, in the example represented, is substantially equal to the dead angle. Preferably, in other variants, angular distance is arranged to be greater than the dead angle. An immediate advantage of the invention is observed in FIG. 4B, namely that the maximum play E2 of a pin configured according to the invention is much smaller than the maximum play E1 of the embodiment of FIG. 3, while the play of pinion 32 in its two tangential positions, corresponding to the situation of FIG. 4A, is identical in the two timepiece movements 2A and 30. In an advantageous variant, the pinion and the toothing are arranged such that, when the pinion is in either of its two tangential positions, the calendar indicator has an angular play that is smaller than or substantially equal to thirty-five microns (35 m). Further, in an initial portion of the dead angle zone defined by dead angle , from the direction 42 tangent to circular toothing 5A, the angular play of the date ring does not vary. This is due to the fact that the arc of a circle 38 has a radius centred on axis of rotation A10 of pinion 32. It will be noted that this initial portion extends here over approximately half of angular distance (corresponding in this example to the angular opening of the pins). By adjusting the profile of the end of the teeth, an even greater angular distance of rotation with constant play is possible. In an advantageous variant, the pinion and the toothing are arranged such that, when the rotating wheel set is subjected to a rotation over all of either one of the two dead angle zones, the date indicator has an angular play that remains less than or substantially equal to forty microns (40 m).

[0031] Owing to the profile of the pins according to the invention, by providing a small play in the two tangential positions of the pinion, it is thus possible to obviate the positioning jumper while ensuring proper positioning of the date ring. Other advantages result from this invention. Firstly, for a width L of the hollows of toothing 5A, the pins are more solid than in the case of FIG. 3. They are therefore stronger and more resistant to shocks. Next, the dead angle and therefore the dead angle zone may still be considerably, notably as large as in an embodiment with conventional cylindrical pins. Finally, the anti-shock function is greatly improved since, in case of shocks, the points of application of the force of the date ring on the pins remains on a tangent intercepting axis of rotation A10 over the entire angular distance of rotation with constant play. Thus, not only in its two tangential positions, but over this entire angular distance, there is no torque exerted on pinion 32 in the event of external shocks causing an angular acceleration of the date ring.

[0032] Referring to FIGS. 5 and 6, two variants of a particular second embodiment will be described below, in which not only do the pins have a specific profile according to the invention, but also the toothing of the calendar indicator. In these two variants, the arc of a circle 38 of the transverse profile of the two pins extends over an angular distance comprised between 3/2 multiplied by the dead angle and substantially two times said dead angle (3/2<<2). It will be noted that this arc of a circle is centred on axis of rotation A10 of the rotating wheel set which is formed by the two pins. Next, in these two variants, each hollow 7B, respectively 7C of toothing 5B, 5C exhibits, at ends 48 of two adjacent teeth 6B, 6C, an opening which has a dimension L1 smaller than the width of the hollow in the area of contact thereof with the two pins, during the driving of the calendar indicator by the rotating wheel set including these two pins, and notably smaller than the maximum width L2 at the bottom of the toothing. The aforementioned contact region extends over a certain distance along side walls 50, respectively 62 of the teeth, beyond tangent 42 to the circular toothing towards the bottom of the toothing.

[0033] Next, each pin 46, respectively 56 has a radial dimension R relative to axis of rotation A10 of the rotating wheel set and a tangential dimension T, perpendicular to the radial dimension, the value of this one tangential dimension being substantially equal to two times that of the radial dimension or greater. It will also be noted that dimension L1 is arranged to be greater than radial dimension R and dimension L2 is arranged to be greater than tangential dimension T, otherwise the meshing of the pinion-pin with the toothing of the calendar indicator cannot function since it will quickly lock.

[0034] In the variant of FIG. 5, the side profile 50 of teeth 6B, respectively of the side edges of hollows 7B, is substantially rectilinear from tangent 42 to the bottom of the toothing. Each hollow 7B is flared towards the bottom of the toothing and thus each tooth 6B is flared towards its end region 48. At the ends of the teeth, the profile of the teeth substantially follows an arc of a circle centred on axis A10. Pins 46 also have a flared shape moving away radially from axis of rotation A10. They have a large opening to considerably increase angular distance of the arc of a circle defined by the outer portion of the tooth. Thus, a small substantially constant play is obtained for almost the entire dead angle distance, which extends approximately over dead angle whose value is approximately equal to 30 for the example represented. Thus, in the event of an external shock, the two pins of the pinion lock the first indicator when the rotating wheel set is angularly within either of the two dead angle zones.

[0035] In the variant of FIG. 6, the inner portion of each of the two pins 56 also has an arc of a circle profile to allow tangential dimension T of the pins to be increased without thereby increasing their radial dimension R. This allows the angular opening of the pins to be increased and thereby the angular distance defined by the outer arc of a circle 38. Teeth 6C have a corresponding profile which is arranged to allow a greater dead angle to be obtained while having a substantially constant small play over the dead angle distance resulting from this dead angle. Each tooth has a root 58 with substantially parallel side walls 62. Next, the width of the teeth increases with a circular profile section 64 centred on axis A10, the radius of this circular profile being arranged to be slightly smaller than that defined by the inner circular portion of the pins. Finally, to facilitate the penetration of the pins inside the toothing and to prevent the gear locking, in their terminal end region, the teeth have a profile section 66 that curves towards axis A10 and enlarges the opening between the ends of two adjacent teeth. The length of section 66 may the relatively large here and extend beyond tangent 42 without adversely affecting the small play over the large dead angle distance which has a value of between 35 and 40 in the example represented.

[0036] In a similar manner to that explained above with reference to FIGS. 1 and 2, in the first and second embodiments, the information of each calendar indicator 4A, 4B and 4C, respectively represented in FIGS. 4, 5 and 6, is a first item of information. Thus, the analogue display is a first analogue display and the calendar indicator is a first indicator. Next, timepiece movement 44, respectively 54 of these two embodiments further comprises a second analogue display (not represented but similar to that of FIGS. 1 and 2) comprising a second indicator, which is kinematically connected to the mechanism driving the first indicator. This second display is arranged such that the second indicator is driven by the drive mechanism to indicate a second item of information independent of the first item of information while the rotating wheel set remains in one or other of the two dead angle zones defined by dead angle a from the two possible tangential positions of the pinion-pin.