HK1229901A1 - Timepiece movement including an analogue display drive device - Google Patents

Description

Timepiece movement including an analog display drive

Technical Field

The invention concerns a timepiece movement including an analogue display drive, in particular for a calendar display.

The invention also relates to a timepiece movement including a device for driving two independent analog indicators by the same drive source, in particular an electromagnetic motor.

Disclosure of Invention

It is an object of the present invention to provide a device for driving an analog display, in particular a date ring in a timepiece movement, which is shock-resistant for the majority of the time.

Another object of the present invention is to provide a driving device for a multifunctional analog display with a single driving source, in particular for driving date rings and chronograph hand drivers by a single motor, which is effective for various functions of the display and allows to actuate at least one function independently with respect to a second function of the display.

It would be advantageous to provide a display drive for a timepiece movement that is cost effective to manufacture.

It would be advantageous to provide a compact display driver for a timepiece movement.

The object of the invention is achieved by a timepiece movement including an analog display drive as described in the following paragraph.

In the invention, a timepiece movement includes an analog display drive for a display disk having a ring gear, including a drive source and a drive mechanism coupling the drive source to the ring gear. The drive mechanism comprises a wheel set with a pin, which wheel set is formed by a gearwheel and a pinion comprising a pin, and an engaging wheel which engages with said gearwheel of the pin wheel set. The pinion with pins comprises two diametrically opposed pins spaced apart by a distance configured to position the pins on either side of either tooth of the ring gear. The gear wheel having a first non-circular profile and the meshing wheel having a second non-circular profile complementary to the first non-circular profile, the gear wheel and the meshing wheel being arranged with respect to each other such that: when the two pins are oriented in the tangential direction of the ring gear, the two wheels have a first transmission ratio that is smaller than a second transmission ratio between the wheels when the two pins are aligned perpendicular to the tangential direction.

According to a preferred embodiment, when two pins are oriented tangentially to the display disk ring gear, the two pins are arranged to define a self-locking system in the event of a shock applying a tangential force to the ring gear.

By "non-circular profile of the wheel" is meant a wheel having a toothing conforming to a general curve other than circular, or a wheel having a toothing generally conforming to a general circular shape but with its axis of rotation not at the centre of the general circular shape. According to a particular embodiment, the non-circular profile of the gear wheel of the pin wheel set is elliptical or substantially elliptical.

According to one embodiment of the present invention, the pin pinion is configured with respect to the display panel gear ring to have a dead angle area (dead angle area) for driving the display panel. The angular distance of the dead angle region is arranged to be greater than 10 degrees. According to a preferred variant, in the event of a shock, when the angular position of the pin pinion is in this dead angle region, the two pins of the pin pinion block the rotation of the display disk.

According to a main embodiment, the gear reduction ratio between the meshing wheel and the pin wheel is greater in the above-mentioned dead angle region than outside said region.

According to an advantageous embodiment, at least one of the wheels of the drive mechanism comprises an additional display element which is operable independently of the display disc in the dead-angle region.

According to one embodiment, the additional indicator wheel is configured to complete at least 360 ° of rotation when the pin pinion undergoes angular movement in the dead angle region. The additional display element may be, for example, a pointer mounted on the spindle of the additional display wheel. In a particular variant, the additional display wheel is a chronograph wheel.

In one embodiment, the drive source comprises an electric motor controlled by an electronic unit of the timepiece movement. The motor may be bi-directional.

Other advantageous objects and aspects of the invention will be apparent from the claims and the following detailed description of the embodiments.

Drawings

The following detailed description will be made with reference to the accompanying drawings, given by way of non-limiting example, in which:

fig. 1 is a schematic perspective view of a display drive device for a timepiece movement according to an embodiment of the invention, showing a date disc moving from one stop position to the next;

figure 2 is a corresponding plan view of the embodiment of figure 1, but with the date disc in a stop position, i.e. rest or non-driving position;

fig. 3A is a view showing a partial enlarged view of fig. 2;

FIG. 3B is a view similar to FIG. 3A, but showing the drive in a dead-angle zone limiting position, in which the date disc remains stationary; and

fig. 3C is a view similar to fig. 3A, but showing the position of fig. 1, in which the date disc is in movement from one stop position to the next.

Detailed Description

Referring to the figures, a timepiece movement 2 includes a display drive device according to one embodiment of the invention. The display is constituted by a display disc 4, and the drive means comprises a drive mechanism 6 and a drive source 8. The drive source 8 may comprise, for example, an electric motor controlled by an electronic unit (not shown) of the electronic timepiece movement. In the present invention, the drive source 8 may also include a mechanical energy source that drives a mechanical motor, or a hybrid system. The invention is particularly useful for a drive source 8 comprising an electric motor, the idle torque of which is low, and in which a mechanism for blocking the drive mechanism 6 in case of shocks is necessary. In the embodiment shown, the electric motor comprises an output pinion 22, which output pinion 22 is coupled to the gear trains 20c, 20b, 20a of the drive mechanism 6. The wheel trains 20c, 20b, 20a are coupled to the display panel 4 via a pin wheel set 10 and an engaging wheel 18 of the pin wheel set. The meshing wheel 18 is fixedly mounted on a further gear wheel 19 coupled to gear trains 20c, 20b, 20 a.

In the embodiment shown, the display disk 4 takes the form of a ring comprising, on its inner periphery, a ring gear 5; the toothed ring 5 meshes with a pin wheel set 10. In a variant (not shown), the toothing 5 may be arranged on the outer periphery of a display disk, which may take the form of a solid disc or ring. In one variation (not shown), the display disk may be a ring or a section of a circular disk; in this case, the display device is bi-directional. In one embodiment, the display disc is a date display disc, i.e. a circular disc indicating the date (a few months). In other embodiments of the invention, the display panel may be used to display any other discrete function, such as the following: "AM/PM", CHR for timer; "GMT"; "TMR" for timers; "AL ON/AL OFF" for turning On/Off an alarm clock.

The pin wheel 10 includes a gear 12 having a non-circular profile 13a and a pin pinion 14 containing a pin 16, particularly a pair of pins 16a, 16 b. The pin pinions 14 may take the form of, for example, a pair of cylindrical pins arranged on the axis of rotation a of the gear 12₁₀And is fastened directly to the gear or to a plate or disc mounted on the gear 12. The pin may also be formed directly as part of the gear 12, for example by injection molding, forming or machining the pin as a single piece with the gear 12.

In the stop position shown in fig. 2 and 3a, the pins 16a, 16b are configured to be arranged on either side of any tooth 5a of the display disc. In this stop position, the pin blocks the rotation of the display disc 4. In fact, in this position, the pair of pins 16 is substantially oriented so as to pass through the axis of rotation a of the pin and pin wheel 10₁₀Corresponds to the tangential direction T showing the direction of rotation of the disk on this engaging tooth, in other words, to the substantially circular tangential direction defined by the ring gear 5 at the position corresponding to the tooth 5 a. A distance d separating the pair of pins 16a, 16b₁₆Corresponding to the thickness d of the teeth 5a₅Plus some clearance to allow the pair of pins to pivot about a tooth, so that the axis of rotation A of the pin pinion₁₀This allows the pins 16a, 16b to be positioned on either side of the tooth 5a and to rotate between two extreme angular limits +/- α with respect to the tangential direction T, the angular distance between these two limits- α and + α forming a dead angle zone for driving the display disc, i.e. an angular zone in which the pin wheel does not drive the date discThe display disk gear ring is configured such that there is a dead-angle region (+/- α) that drives the display disk, which is greater than conventional backlash<|α|)。

The distance between the pins, the dimensions of the teeth and the position of the axis of rotation of the pin pinion are preferably configured so that the absolute value of the two extreme angles +/-a with respect to the tangential direction T is above the maximum conventional flank clearance angle in the train (in the poor example about 5 °) until, in a preferred variant, substantially expanding to the end of the self-locking zone (which is in particular between +/-10 ° and +/-20 ° depending on the drive mechanism) which allows the disc to be blocked in the event of shocks. However, according to a variant of this embodiment, the dead zone can be enlarged outside this limit. Thus, the angular distance may be greater than 40 °. In the example shown in fig. 3B, this angular distance is substantially equal to 90 ° (+/-45 °). However, in one particular embodiment (which has additional functionality to be discussed below), the use of this dead band may be intentionally limited to the angular locking region of the pin wheel. In this angular locking region, when a rotational force is applied to the display disc 4, for example due to inertial forces resulting from a shock, the tooth 5a engages with one or other of the pins 16a, 16b, which blocks rotation of the display disc relative to the drive mechanism 6. According to two particular modes, the dead angle region between the limit angles- α and + α or the angle locking region (provided that the angular distance of the angle locking region is less than or equal to the angular distance of the dead angle region) can be used for other additional functions, such as a timer function, since the display disc 4 is held in its rest position between the limit angles- α and + α.

In the example shown, additional functions may be performed by one or more hands 24 mounted on one or more spindles of the respective wheels 20a, 20b, 20c of the train coupling the drive source 8 to the pin wheel 10. In the example shown, one of the wheels is a chronograph wheel 20a, this chronograph wheel 20a having an arbour on which a chronograph hand 24 is mounted, the gear reduction ratio between this wheel and the pin pinion 14 being such that: when the wheel completes one revolution, the pin pinion completes at most an angular rotation of an angle α corresponding to half the angular distance of the dead angle region +/- α. In this chronograph function, when the chronograph hand 24 has completed one revolution, the electric motor returns it, so that counting can be continued without the position of the display panel 4 being thereby changed. The timer wheel may be used to indicate seconds, minutes or hours, for example. Thus, in the dead-angle region from- α to + α, the respective wheels 20a, 20b, 20c of the train coupled to the drive source 8 can be used for any desired function without thereby impeding the display of the display panel 4; this makes it possible to reduce the number of motors required in the timepiece movement for a number of desired functions. Of course, depending on the desired reduction ratio and display, a different wheel of the train than that used in the illustrated example, or an additional wheel in meshing relationship with one of the wheels of the train, may be used for the desired function.

According to one aspect of the invention, the gear wheel 12 of the pin wheel set 10 and the meshing wheel 18 of the pin wheel have non-circular profiles 13a, 13b, which profiles 13a, 13b are configured such that the angular rotation is slower in the dead angle region than in the active region (outside the dead angle region). This makes it possible to quickly display transitions outside the dead-angle region. A first advantage is that this allows the display disk 4 to change position rapidly, in particular minimizing the time interval during which the pin pinion 14 is outside the following angular region: that is, in this angular region, there is no guarantee that the pin pinion will block the display disk 4 in the event of a shock or other inertial torque being applied to the display disk with respect to the drive mechanism 6.

In addition, the configuration in the illustrated embodiment is such that the gear reduction ratio between the engaging wheel 18 and the pin wheel 10 in the dead-angle region is larger than when the pin wheel 10 is in the active region (outside the dead-angle region). This enables the gear reduction ratio required in the drive to be reduced to achieve one full rotation of the timer wheel 20a while still remaining properly in the dead-angle region-/+ α. In a preferred embodiment, the additional display wheel 20a is configured to be able to complete at least a 360 ° rotation during angular movement in the dead angle region. In the present invention, for a given minimum drive torque necessary to drive the display disk via the pin pinion, an angular region corresponding to the dead angle region of the pin wheel set is produced on wheel 20a, which is greater than in the case of a circular wheel with a central axis of rotation. The maximum angular distance traveled by the wheel 20a associated with the additional indicator 24 is achieved by a maximum speed increasing gear transmission and thus a maximum gear reduction between the pin pinion 14 and the wheel 20a for one rotation of the pin pinion 14 through the limit angle a of the dead angle region. Therefore, in this dead angle region near the tangential position of the two pins 16a, 16b, there is a large gear reduction between the wheel 20a and the pin pinion 14. Thus, the wheel 20a can complete a considerable angular range of rotation without significant movement of the display disc 4.

In one embodiment, the non-circular profile 13a of the gear 12 may have, for example, an elliptical or substantially elliptical shape; the non-circular profile 13b of the engagement wheel 18 of the peg wheel is thus complementary. In the example shown, the non-circular profile 13b of the engagement wheel 18 of the pin wheel is about the axis of rotation a of said wheel₁₈Is eccentric. Thus, for each revolution of pin wheel set 10, engaging wheel 18 completes two revolutions. The profile of the teeth may be configured as point or line contacts to minimize friction; these profiles can be defined using known methods.

In a preferred embodiment, the timepiece movement further comprises a jumper (jumper) for positioning the display disk, the jumper being arranged to hold the display disk in a plurality of different display positions. In an advantageous variant, substantially identical tangential tooth flank clearances are provided between the two tangentially oriented pins 16a, 16b and the respective teeth 5a of the ring gear 5 inserted between the two pins when the display disk is in any one of a plurality of different display positions.

In the example shown, the drive pinion 22 is coupled to the wheel 19 on which the pin wheel engagement wheel 18 is mounted by 3 successive wheels 20c, 20b, 20a, but of course there may be a different number or arrangement of wheels in the drive 6, depending on the characteristics of the drive source 8, the gear reduction ratio between the individual wheels of the gear trains 20a, 20b, 20c, the display disc size and the additional display function required.

Advantages of embodiments of the invention include, inter alia: the bidirectionality of the display disk, the optimization of the time during which the display disk remains in the blocked position, a compact mechanism with few components and the possibility of incorporating this technology in the modular platform of a traditional timepiece movement.

List of reference numerals

Clock movement 2

Date display disc 4

Gear ring 5

Tooth 5a

Display driving device

Drive mechanism 6

Pin gear set 10

Axis of rotation A₁₀

Gear 12

Non-circular profile 13a

Pin pinion 14

Pin 16 (a pair of pins 16a, 16b)

Engaging wheel 18 (for pin wheel)

Non-circular profile 13b

Axis of rotation A₁₈

Gear 19

Wheels 20a, 20b, 20c

Additional display wheel (e.g. chronograph wheel) 20a

Drive source 8

Drive pinion 22

Electric motor

Additional display pointer 24

Limiting angle alpha of the dead angle region (half the angular distance of the region)

Direction of T tangent

d₁₆The pair of pins are separated by a distance

d₅Thickness of one tooth

Claims (15)

1. A timepiece movement comprising a drive device for driving an analog display (2) constituted by a display disc (4) including a ring gear (5), the drive device including a drive source (8) and a drive mechanism (6) coupling the drive source (8) to the ring gear (5), the drive mechanism including a pin wheel set (10) and an engagement wheel (18), the pin wheel set (10) being formed by a toothed wheel (12) and a pin pinion (14), the engagement wheel (18) being in engagement with the toothed wheel, the pin pinion including diametrically opposed spaced apart distances (d)₁₆) Is arranged at a distance of two pins (16a, 16b) of the pair-positioning the two pins on either side of any tooth of the toothing (5), characterized in that the toothed wheel has a first non-circular profile (13a) and the meshing wheel (18) has a second non-circular profile (13b) complementary to the first; and, the gear and the meshing wheel are arranged with respect to each other such that: when the two pins are oriented in the tangential direction (T) of the ring gear, the gear and the meshing wheel have a first transmission ratio that is smaller than a second transmission ratio between the gear and the meshing wheel when the two pins are aligned perpendicular to the tangential direction.

2. Timepiece movement according to claim 1, wherein the two pins, when oriented substantially tangentially to the toothing of the display dial, are arranged so as to define a self-locking system in the event of the timepiece movement being subjected to shocks that apply tangential forces to the toothing.

3. Timepiece movement according to claim 1 or 2, characterised in that the pin pinion is configured with respect to the toothing of the display disk such that there is a dead angle region (+/-a) for driving the display disk, and that the angular distance of this dead angle region is greater than 10 degrees (5 ° < |).

4. Timepiece movement according to claim 3, wherein, in the event of a shock, the two pins of the pin pinion block the rotation of the display disk when the angular position of the pin pinion is in the dead angle region.

5. A timepiece movement according to claim 3, wherein the gear reduction ratio between the meshing wheel (18) and the pin wheel set (10) is greater in the dead-angle region than outside the dead-angle region.

6. Timepiece movement according to claim 3, wherein at least one additional display wheel (20a) of the drive mechanism (6) comprises an additional display element (24) which can be operated in the dead-angle region (-/+ α) without changing the position of the display disc (4).

7. Timepiece movement according to claim 6, wherein the additional display wheel (20a) is configured so as to be able to complete at least 360 ° of rotation during the angular movement in the dead angle region.

8. Timepiece movement according to claim 6, wherein the additional display element is a pointer (24) mounted on an arbour of the additional display wheel (20 a).

9. The timepiece movement of claim 8, wherein the additional display wheel forms a chronograph mechanism.

10. A timepiece movement according to claim 3, further comprising a jumper for positioning the display disk, the jumper being arranged to hold the display disk in a plurality of different display positions.

11. The timepiece movement according to claim 10, wherein there is substantially the same tangential tooth flank clearance between the two pins oriented tangentially and the corresponding teeth of the ring gear inserted between the two pins when the display dial is in any one of the plurality of different display positions.

12. Timepiece movement according to claim 1, wherein the drive source is constituted by a bidirectional electric motor controlled by an electronic unit of the timepiece movement.

13. The timepiece movement of claim 1, wherein the display dial is a date ring.

14. Timepiece movement according to claim 6, wherein the drive source is constituted by a bidirectional electric motor controlled by an electronic unit of the timepiece movement.

15. The timepiece movement of claim 6, wherein the display dial is a date ring.