HK1213648B - Timepiece with a global time display - Google Patents

Abstract

The present invention relates to a timepiece with a global time display, comprising: a timepiece mechanism, - a first indicator for displaying local time and intended to be driven by the movement at one revolution in twelve hours, - a twenty-four hour dial (12) connected kinematically to the first indicator and driven synchronously therewith, and intended to be driven by the movement at one revolution in twenty-four hours, - a cities dial (14) that bears indications for identifying at least a number of time zones of the world and is able to rotate with respect to the twenty-four hour dial (12), and - an adjusting member (20) for adjusting the global time. The timepiece according to the invention furthermore comprises a kinematic link between the twenty-four hour dial (12) and the cities dial (14), said kinematic link having a kinematic transmission crown wheel (24) interposed between the twenty-four hour dial (12) and the cities dial (14), the adjusting member (20) for adjusting the global time being able to drive said kinematic transmission crown wheel (24). In addition, there are a first unidirectional drive system (28) and a second unidirectional drive system (30) upstream and downstream, respectively, of the kinematic transmission crown wheel (24), the kinematic transmission crown wheel (24) being kinematically linked to the twenty-four hour dial (12) by a linkage train (26) which incorporates the first unidirectional drive system (28).

Description

Watch displaying world time

Technical Field

The invention relates to the field of timepieces, in particular to a universal time watch. World time watches allow the current time in different time zones of the world to be displayed simultaneously. As shown in fig. 1, such a watch includes, in addition to a pointer 10 that can indicate the local time, a 24-hour disc 12 and a city disc 14 that represents different time zones in the world.

The pointer allows to indicate the time of the time zone in which the selected city is usually located at noon, and this time can be conveniently indicated by a specific fixed mark 16 on the dial. The 24-hour disc 12 is driven by the movement and is kinematically connected to the hour hand in order to display the time of different time zones of the world.

Background

In such tables, the correction of different indicators has been problematic. In fact, these watches usually comprise two correction mechanisms, one for local time and the other for universal time. The correction device of the world time system drives only the city wheel and the 24 hour wheel, and the 24 hour wheel is driven again during the adjustment of the hand time. Such adjustments are not intuitive at all.

Subsequently, correction means are proposed which allow to de-synchronize the rotation of the 24-hour disc with the city disc 14, so as to correct either all the wheels or, as required, only the position of the hands and of the 24-hour disc.

These devices are very complex. In document CH690205, the hour hand is supported by an hour star wheel, which is rigidly connected to the hour wheel of the movement by a jumper during normal operation. The corrector started by the push rod drives the city star wheel, the city star wheel cooperates with the city jumper and the return spring thereof, and the city star wheel can drive the hour star wheel through the hour correction wheel by means of the hook. However, when the correction device is activated, the torque of the jumper connecting the hour star wheel and the 24 hour wheel must be overcome, which generates a parasitic torque on the movement. Furthermore, the use of a push rod may exert excessive force on the city disk 14, which may be driven too far due to its large inertia.

Furthermore, the document CH703258, in which a universal time watch is disclosed, in which the time zones are indicated by a universal time zone indicating means, may be cited. The watch comprises a city disk rigidly connected to a city eccentric and concentric with an hour disk. During normal operation of the watch, the city disk remains stationary and the hour disk rotates relative to the city disk. In the time zone correction process, the world time zone indicating means and the local time indicating means are rotated in the same direction together. However, the device is complicated and the volume of the movement increases.

The object of the present invention is to propose a watch displaying universal time and equipped with correction means not having the above-mentioned drawbacks.

Disclosure of Invention

More precisely, the invention relates to a watch displaying the world time, comprising:

a movement;

a first indicator which displays the local time and is driven by the movement according to 12 hours and 1 circle;

a 24-hour disk which is connected to the first indicator in a moving manner, is driven synchronously with the first indicator, and is driven by the movement according to 12-hour 1-turn;

a city disk carrying an indication that allows identification of at least some specific world time zones and that rotates relative to the 24 hour disk; and

a world time adjustment mechanism.

The watch according to the invention also comprises a kinematic connection between the 24-hour disc and the city disc. The kinematic connection comprises a transmission crown wheel interposed between the 24-hour disk and the city disk, the universal time adjustment mechanism being adapted to drive said transmission crown wheel. The watch according to the invention also comprises a first and a second unidirectional drive system respectively upstream and downstream of the transmission crown. Thus, the first indicator and the 24 hour disk remain synchronized, and the city disk, which is driven only during the world time adjustment, is always synchronized with the first indicator and the 24 hour disk.

Drawings

Other details of the invention will become apparent upon reading the following description and upon reference to the accompanying drawings in which:

fig. 1, as already mentioned previously, mainly illustrates a watch displaying world time;

FIGS. 2, 3 and 4 show the device of the watch according to the invention in different operating configurations;

fig. 5 presents an enlarged view of a unidirectional drive system that can be used in the watch according to the invention.

Detailed Description

Fig. 2 shows a table showing world time according to the present invention. Such a watch comprises a movement capable of indicating the current time. This current time information is typically related to the local time (i.e. the time of the location where the wearer is located). In the present invention, the local time is provided by a first indicator, typically by a set of hands 10, one of which indicates the hour and is driven by the movement in 1 cycle, typically 12 hours. The local time may also be displayed in a 24 hour period. In particular, the hour hand is mounted on an additional hour wheel 18. The additional hour wheel co-rotates with the hour wheel of the movement, but a frictional connection, or a ratchet mechanism such as one implementing a ratchet and a star wheel, may be used to disconnect the additional hour wheel from the hour wheel. As will be understood hereinafter, this device allows the use of the universal time adjustment mechanism 20 to adjust the display of the local time, thereby limiting the disturbance to the operation of the movement.

The first indicator is movably connected by a gear train 22 to a second indicator in the form of a 24 hour disk 12 with a 24 hour day number indication. Gear set 22 reduces the rotational speed of the first indicator so that the second indicator is driven by the movement in 1 cycle for 24 hours. For actuation of the second indicator, the 24 hour disc 12 includes internal gear teeth 12a that mesh with the gear set 22. Since the gear set 22 is always engaged by the first and second indicators, the first and second indicators remain synchronized. The 24-hour disk 12 may also be divided into two equal sections having different colors to provide day and night indications. Another method of describing day and night may also be selected.

The watch according to the invention also comprises a third indicator in the form of a city disk 14. The city disk includes 24 location indicators, each location indicator corresponding to a time zone. City disk 14 may also indicate a half time zone or a quarter time zone.

City disk 14 is mounted for rotational movement relative to 24 hour disk 12. As described in detail below, the city disk is rotationally driven by means of a universal time adjustment mechanism 20. City disk 14 is associated with positioning cogs 23, the number of teeth of which corresponds to the number of time zones indicated, in order to index the position of city disk 14 according to the support of pogo sticks 25.

The watch also includes a kinematic connection between the 24 hour disk 12 and the city disk 14. This kinematic connection is achieved by a transmission crown wheel 24 interposed between the 24-hour disc 12 and the city disc 14. In the example provided, the transmission crown wheel 24 comprises double teeth, i.e. inner 24a and outer 24b teeth. The internal toothing 24a allows the kinematic coupling of the transmission crown wheel 24 to the internal toothing 12a of the 24-hour disc 12 by means of a coupling gear 26, which integrates (int grer) a first unidirectional drive system 28.

Within the meaning of the present application, a unidirectional drive system refers to a system which transmits the received rotational motion to the driven wheel when driven in a first direction. However, when driven in the second direction, the unidirectional drive system does not transmit rotational motion to the driven wheel. It should be noted, however, that the one-way drive system remains engaged with the driven wheel, and therefore it must be distinguished from the coupling system. Such a unidirectional drive system may be a unidirectional bearing provided by MPS Micro Precision Systems AG, or may be a unidirectional gear of the kind described in the applicant's application document CH 700806.

Thus, in the embodiment provided, the first unidirectional drive system 28 is of the unidirectional bearing type. The unidirectional drive system is arranged to: rotation of 24-hour disc 12 in the normal operating direction (i.e. the driving direction of the movement) (counterclockwise in the example) does not drive the transmission crown 24 and therefore does not drive city disc 14.

For kinematic connection of the transmission crown 24 and the city disk 14, the watch comprises at least one second unidirectional drive system 30. The watch therefore has first and second unidirectional drive systems 30 respectively upstream and downstream of the transmission crown wheel 24. The upstream and downstream directions are defined in terms of the direction of energy transfer in the drive train.

In order to improve the stability of the city disk, it is possible to have a plurality of unidirectional drive systems of the unidirectional gear type regularly distributed on the city disk 14 and connecting the city disk to the transmission crown wheel 24. In the example illustrated in detail in fig. 5, the second unidirectional drive system 30, selectively mounted on the city disk 14, comprises a driven pinion 32 coupled to a locking wheel 34, which meshes with the external toothing 24b of the transmission crown wheel 24. The lock wheel 34 is engaged with two lock pinions 36. The tooth shape of the locking wheel 34 is arranged: the lock wheel drives the lock pinion 36 when the lock wheel is rotated in the first direction, and the lock wheel is locked against the lock pinion 32 when the lock wheel is rotated in the second direction. Reference may be made to the aforementioned swiss patent for details regarding the geometry of the teeth in order to achieve these effects.

Finally, the watch according to the invention also comprises a world time adjustment device adapted to drive the transmission crown 24 in a direction to lock the locking wheel 34 against the locking pinion 36. The adjustment device comprises an adjustment mechanism 20, typically in the form of a second crown wheel, separate from the master spindle, which adjusts the local time as usual and provides energy or performs other functions, such as correcting the date, if necessary. The second crown wheel is mounted on the second mandrel 38, which should preferably be axially stretched to activate the adjustment means and connect the adjustment mechanism 20 with the transmission crown wheel 24. The adjustment mechanism can also be realized in the form of a push rod driving a transmission crown gear.

In operation, the elements operate as follows: in normal operation (fig. 2), the additional hour wheel 18 is driven in the direction of the hands of the watch and the 24-hour disk 12 is driven in the opposite direction. The wheels of the linkage gear 26, which are located between the transmission crown 24 and the first unidirectional drive system 28, are driven. Conversely, the wheels of the linkage gear 26 located between the first unidirectional drive system 28 and the transmission crown gear 24 are not driven. City disk 14 is therefore stationary. Advantageously, it is noted that the first unidirectional drive system 28 is placed relatively early in the different kinematic chains, which allows a small number of components to be driven by the movement under normal operation.

The same operation is obtained during local time correction in the clockwise direction using the control spindle.

In correcting the local time using the control spindle, in the anticlockwise direction (figure 3), the additional hour wheel 18 is driven in the anticlockwise direction, while the 24-hour disc 12 is driven in the clockwise direction (i.e. in the opposite direction to the normal operating direction resulting from the movement drive). In this configuration, the first unidirectional drive system 28 transmits the received rotational motion so that all wheels of the linkage gear 26 and the transmission crown gear 24 are driven. The lock wheel 34 drives the lock pinion 36, which rotates "under vacuum". City disk 14 is not driven and is held in place by a spring jumper 25 cooperating with positioning cog 23. In this case, more elements are driven than ever, but since the driving is manual, there is no disadvantage.

Finally, in case of adjustment of the universal time by the adjustment mechanism 20 (fig. 4), the adjustment mechanism is arranged to drive the transmission crown wheel 24 in a counter clockwise direction through the inner gear teeth 24 a. In this case, the 24-hour disk 12 is driven by the linked gear 26 and the first unidirectional drive system 28. The 24 hour disk is driven in the normal operating direction (i.e., counterclockwise) as driven by the cartridge. In fact, in contrast to the normal drive, in which the first unidirectional drive system does not transmit any rotation, the traction comes from the transmission crown wheel 24 instead of the 24-hour disc 12, even if the direction of rotation is the same. In contrast, the effect is similar to the reversal of the direction of rotation, and the first unidirectional drive system 28 is also employed to transmit the rotation. Likewise, city disc 14 is rotationally driven by drive crown 24 under the action of second unidirectional drive system 30.

Thus, the adjustment of world time allows all of the indicating mechanisms to be actuated in a single operation, with the 24 hour disk 12 and city disk 14 rotating in a clockwise direction and the hands rotating in a counterclockwise direction. As mentioned above, the fact that the hour hand is mounted on the additional hour wheel 18 limits the disturbances on the movement during the adjustment of the universal time. Whereas city disk 14 rotates in 1/24-turn steps (due to spring jumper 25 and positioning cog 23), the hour hand jumps in 1/12-turn steps in synchronism and connection with 24-hour disk 12.

The device requires few components compared to other more complex world time systems. The elements involved are almost exclusively wheels which rotate independently, which makes the device reliable and simple. All wheels are permanently engaged, which makes it impossible to de-index. In addition, even if the user forgets to push back the second spindle, the movement can still work normally. The one-way drive system prevents damage and retains the index of the various indexing mechanisms in the event that the second spindle 38 is pulled out during adjustment on the master spindle.

The examples of unidirectional drive systems may be interchanged. For example, instead of a one-way gear, a one-way bearing of the first system may be used, or the city disk 14 may be connected to a transmission crown wheel 24 by means of a one-way bearing, which forms an integral ring around the movement. The transmission crown gear 24 then only kinematically connects the inner gear teeth to the linkage gear 26 and to the adjustment mechanism 20. Other types of unidirectional drive may be implemented as well, such as ratchet-reverser systems of the type used on self-winding gears.

Other alternatives may be considered by those skilled in the art without departing from the scope of the invention as defined in the claims. In particular, gear sets and linked gears may be changed or modified.

Claims (10)

1. A watch that displays world time, comprising:

a movement;

a first indicator displaying local time and driven by the movement in 12 hours and 1 cycle;

a 24-hour disk (12) kinematically connected to and driven synchronously with said first indicator and driven by said movement according to 1 cycle for 24 hours;

a city disk (14) carrying an indication that allows identification of at least some specific world time zones and that rotates relative to the 24 hour disk (12); and

a world time adjusting mechanism (20),

said watch also comprising a kinematic connection between said 24-hour disc (12) and said city disc (14), said kinematic connection comprising a transmission crown wheel (24) interposed between said 24-hour disc (12) and said city disc (14), said world time adjustment mechanism (20) being adapted to drive said transmission crown wheel (24),

characterized in that it comprises a first unidirectional drive system (28) and a second unidirectional drive system (30) respectively upstream and downstream of said transmission crown wheel (24), and in that said transmission crown wheel (24) is kinematically connected to said 24-hour disc (12) by means of a linking gear (26) which integrates said first unidirectional drive system (28), and in that said transmission crown wheel (24) and said city disc (14) are kinematically connected by means of said second unidirectional drive system (30).

2. Watch according to claim 1, characterised in that said first unidirectional drive system (28) is arranged to: the rotation of the 24-hour disc (12) in the normal operating direction, i.e. in the driving direction of the movement, does not drive the city disc (14).

3. A watch according to claim 2, characterised in that the first unidirectional drive system (28) is arranged to: the rotation of the 24-hour disk (12) in the normal operating direction, i.e. in the driving direction of the movement, does not drive the transmission crown wheel (24).

4. A watch according to claim 3, characterised in that the first unidirectional drive system (28) is arranged to: -the rotation of the 24-hour disc (12) in a direction opposite to the normal operating direction drives the transmission crown wheel (24) in a first direction, and-the second unidirectional drive system (30) is arranged: -not driving the city disc (14) when the transmission crown wheel (24) is driven in the first direction.

5. Watch according to claim 4, characterized in that it comprises a world clock adjustment device adapted to drive the transmission crown (24) in a second direction opposite to the first direction.

6. A watch according to claim 5, characterised in that the first unidirectional drive system (28) and the second unidirectional drive system (30) are arranged to: the 24 hour disc (12) is driven in a normal operating direction when the transmission crown wheel (24) is driven in the second direction by the universal time adjustment device.

7. A watch according to any one of claims 1 to 6, characterised in that at least one of the unidirectional drive systems comprises a unidirectional bearing.

8. A watch according to any one of claims 1 to 6, characterised in that at least one of the unidirectional drive systems comprises a unidirectional gear.

9. Watch according to claim 8, characterized in that at least one of said unidirectional drive systems comprises a driven pinion (32) coupled with a locking wheel (34) meshing with two locking pinions (36), the wheel tooth shape of said locking wheel being arranged: the lock wheel drives the lock pinion when the lock wheel is rotated in the first direction, and the lock wheel is locked against the lock pinion when the lock wheel is rotated in the second direction.

10. A watch according to any one of claims 1 to 6, characterised in that at least one of the unidirectional drive systems comprises a commutator system.