HK40081917B - Horological mechanism for displaying at least the single time indication and timepiece comprising such a mechanism - Google Patents

Description

Clock mechanisms for displaying at least a single time indication and clocks including such mechanisms.

Technical Field

This invention relates to a clock mechanism for displaying at least a single time indication. The invention also relates to a clock incorporating such a mechanism.

Background Technology

In mechanical watchmaking, the gear train and pinions are collectively known as the final gear train. It transmits driving force from the mainspring barrel to the escapement mechanism to maintain the oscillation of the regulating element, typically the balance wheel, which adjusts the rate of the watch movement through its oscillation. Among the various pinions and wheels that make up the final gear train is a central moving mechanism (mobile). The minute wheel, which rotates once per hour and controls the hand train, is frictionally connected to this central moving mechanism. The rotation of the minute wheel is transmitted to the hour hand via the hand train.

The drawback of the mechanism briefly described above is that the drive gears involve a large number of small gears and wheels, which means that the rotation of these toothed moving parts has backlash and eccentricity problems, which will of course negatively affect the accuracy of the time display.

These issues related to the accuracy of time display are particularly troublesome when one hopes to provide time indication using a single hour hand. In fact, in such cases, even the slightest inaccuracy in driving that hour hand can cause a single time display error of several minutes.

Summary of the Invention

The object of the present invention is to overcome the above-mentioned problems and other problems by proposing a clock mechanism that allows for at least a single time indication with improved accuracy.

Therefore, the present invention relates to a watch mechanism comprising: a barrel drum mounted in a manner that allows free pivoting about a mainspring spool; a mainspring spring housed within the barrel, the mainspring spring comprising a first outer coil and a final inner coil, the mainspring spring being attached to the barrel via the first outer coil and to the mainspring spool via the final inner coil, the mainspring spring being wound via a winding lever engaging with the barrel via a winding gear train; and a mainspring ratchet. The watch mechanism, fixedly mounted on the mainspring shaft, also includes a final gear train comprising a first final wheel that meshes with the mainspring barrel ratchet and transmits driving force from the mainspring barrel to the escapement mechanism. The purpose of this escapement is to maintain the oscillation of the regulating member, which adjusts the timekeeping error of the watch movement through its oscillation. The watch mechanism also includes an hour wheel, which is frictionally mounted on the mainspring shaft and to which the hour hand is attached. The entire kinematic chain extending from the mainspring barrel ratchet to the escapement mechanism is calculated such that the mainspring barrel ratchet and thus the hour wheel rotate at a rate of one full revolution in 12 or 24 hours.

Due to these features, the present invention provides a watch mechanism comprising a mainspring barrel on which an hour wheel is mounted. In this respect, the present invention differs from conventional embodiments, in which the minute wheel is attached, for example, to the shaft of the center wheel of the final gear train and connected to the hour wheel via one or more moving parts. Because the present invention teaches that the hour wheel is mounted directly on the mainspring shaft, the connection between the hour wheel and the escapement is as direct as possible. This allows for the avoidance, as much as possible, of the backlash and eccentricity problems of toothed moving parts often encountered in the motion transmission between the minute and hour wheels, thereby ensuring accurate time display. To achieve this result, two measures are necessary: firstly, the entire kinematic chain extending from the mainspring barrel ratchet to the escapement must be calculated, such that the mainspring barrel ratchet, and therefore the hour wheel, rotates at a rate of one full revolution in 12 or 24 hours; secondly, the hour wheel must be mounted on the mainspring shaft, with the winding of the mainspring spring accomplished by a winding rod that does not engage with the mainspring barrel ratchet fixedly mounted on the mainspring shaft, but rather with the mainspring drum, and the mainspring barrel ratchet engages with the first gear of the final gear train. Another advantage of the invention is evident in the fact that space is saved by eliminating one or more speed reduction mechanisms between the minute wheel and the hour wheel. Similarly, by attaching the hour wheel to the mainspring shaft, the mainspring drum can be arranged at the center of the movement, thus allowing it to be larger than in cases where a smaller diameter mainspring drum is required, i.e., when the mainspring drum is located close to the hands. Therefore, the present invention provides a watch mechanism with a greater power reserve.

According to a particular embodiment of the invention, a minute wheel is attached to the shaft of a wheel in a final gear train, which is calculated such that the minute wheel completes one full rotation in 60 minutes.

The present invention also relates to a timepiece, particularly a wristwatch, that includes such a timekeeping mechanism.

Attached Figure Description

Other features and advantages of the invention will become more apparent from the following detailed description of one embodiment of a clock mechanism according to the invention, which is given in conjunction with the accompanying drawings, in which:

Figure 1 is a top view of the watch movement section between the mainspring drum and the regulating mechanism, which are connected to each other by means of the final gear train and the escapement;

Figure 2 is a perspective view of the watch movement shown in Figure 1;

Figure 3 is an elevation sectional view of the clock mechanism according to the present invention;

Figure 4 is a perspective view of the clock mechanism shown in Figure 3, and

Figure 5 shows the frictional connection between the hour wheel and the mainspring shaft.

Detailed Implementation

This invention originates from the general inventive concept of displaying a single time by means of an hour wheel attached to the shaft of the mainspring barrel. By implementing this, one or more moving parts typically used in watchmaking mechanisms to ensure deceleration between the minute and hour wheels can be eliminated, thus avoiding the inherent backlash and eccentricity problems in these moving parts, which are causes of inaccurate time display. To achieve this result, the invention teaches that the winding of the mainspring barrel spring is accomplished by means of a winding rod, which, instead of engaging with the mainspring barrel ratchet as is usually the case, engages with the mainspring barrel itself, while the mainspring barrel ratchet meshes with the first gear of the final gear train. By properly calculating the number of teeth and diameter of the various gear trains that make up the motion chain extending from the mainspring barrel ratchet through the final gear train to the escapement, the mainspring barrel ratchet, and thus the hour wheel, can be rotated at a rate of one full revolution in 12 or 24 hours. According to a particular embodiment of the invention, the minute wheel is mounted on the shaft of a wheel of the final gear train, which is arranged such that the minute wheel rotates one full revolution in 60 minutes.

Figures 1 and 2 are top and perspective views, respectively, of the watch movement portion in which the watch mechanism according to the present invention is integrated. The watch movement, generally indicated by general reference numeral 1, includes a mainspring drum 2 at its center, mounted in a manner that allows free pivoting about a mainspring shaft 4. The mainspring barrel spring 6, housed within the mainspring drum 2, typically includes a first outer coil 6a, through which the mainspring barrel spring 6 is attached to the mainspring drum 2, and a final inner coil 6b, through which the mainspring barrel spring 6 is attached to the mainspring shaft 4. According to the present invention, winding of the mainspring barrel spring 6 is accomplished by a winding gear train 8, actuated by a winding lever 9 (see Figure 4), and engaging with the mainspring drum 2 itself, rather than with a mainspring barrel ratchet 10 fixedly mounted on the mainspring shaft 4 as is usually the case.

According to another feature of the invention, the watch mechanism further includes a final gear train 12, which includes a first final wheel 14 that meshes with the mainspring barrel ratchet 10. The first final wheel 14 meshes with a central pinion 16, which, together with a central wheel 18, forms a central movement 20. Subsequently, the central wheel 18 meshes with a third pinion 22, which, together with a third wheel 24, forms a third movement 26. Next, the third wheel 24 meshes with a second pinion 28, which, together with a second wheel 30, forms a second movement 32. Finally, the second wheel 30 meshes with an escapement pinion 34, which, together with an escapement wheel 36, forms an escapement movement 38. Due to the driving force it receives from the mainspring barrel 2, the escapement movement 38 is able to maintain the oscillation of the regulating member 40, which adjusts the timekeeping error of the watch movement 1 through its oscillation. According to one exemplary embodiment given for purely illustrative purposes only, the speed regulating member 40 is composed of an assembly formed by a balance wheel 42 and a hairspring 44, and engages with the escape wheel 36 via an anchor escape fork 46.

According to another feature of the invention, the hour wheel 48 is elastically connected to the mainspring shaft 4 in a manner that will be described in more detail below. Referring to Figure 3, it can be seen that the assembly formed by the mainspring shaft 4 and the hour wheel 48 pivots between the first bridge plate 50a and the second bridge plate 50b by means of jewels 52a, 52b acting as bearings. According to yet another feature of the invention, the number of teeth and diameter of the gear train constituting the entire kinematic chain extending from the mainspring barrel ratchet 10 to the escapement mechanism 38 are calculated such that the hour wheel 48, to which the hour hand 54 is attached to indicate a single hour, rotates at a rate of one full revolution in 12 or 24 hours.

The watch mechanism according to the invention operates as follows. To wind the mainspring barrel spring 6, the winding lever 9 is actuated, and as described above, the winding lever 9 engages with the mainspring drum 2 via the winding gear train 8. Actuation of the winding lever 9 causes the mainspring drum 2 to rotate and drive the first outer coil 6a of the mainspring barrel spring 6, through which the mainspring barrel spring 6 is attached to the mainspring drum 2. Simultaneously, the last inner coil 6b, used to attach the mainspring barrel spring 6 to the mainspring shaft 4, remains attached, causing the mainspring barrel spring 6 to tighten. Then, during operation, the mainspring barrel spring 6 begins to relax. When the mainspring drum 2 subsequently comes to rest, the mainspring barrel spring 6, through its last inner coil 6b, pivots the mainspring shaft 4, and thus the mainspring barrel ratchet 10. Therefore, the driving force generated by the relaxed mainspring spring 6 is transmitted to the escapement 38 via the mainspring ratchet 10 and the final gear train 12. Its purpose is to maintain the oscillation of the balance wheel 42, which regulates the timekeeping error of the watch movement 1 through its oscillation. As described above, the number of teeth and diameter of the gear train constituting the entire kinematic chain extending from the mainspring ratchet 10 to the escapement 38 are calculated such that the hour wheel 48, attached to the hour hand 54 to indicate a single time, rotates at a rate of one revolution in 12 or 24 hours.

As described above, the hour wheel 48 is frictionally connected to the mainspring shaft 4 to allow adjustment of a single time display. For this purpose, the hour wheel 48 is connected to the mainspring shaft 4 by means of a friction wheel 56 disposed between the mainspring drum 2 and the hour wheel 48. As can be seen from Figure 5 attached to this patent application, the friction wheel 56 is provided with two flexible arms 58 that clamp the mainspring shaft 4, such that the friction wheel 56 is elastically connected to and rotated by the mainspring shaft 4. The hour wheel 48 is then placed on the friction wheel 56 such that two lugs 60 standing on the surface of the friction wheel 56 engage in two corresponding openings 62 formed in the hour wheel 48, which ensures the rotational connection between the hour wheel 48 and the friction wheel 56.

It goes without saying that the invention is not limited to the embodiments just described, and those skilled in the art can contemplate various modifications and simple variations without departing from the scope of the invention as defined by the appended claims. In particular, according to a specific embodiment of the invention, a minute wheel is attached to the axle of a wheel of a final gear train 12, which is calculated such that the minute wheel completes one full rotation every 60 minutes. The invention also relates to a timepiece, such as a wristwatch, incorporating this horological mechanism. The horological mechanism according to the invention can be advantageously arranged such that the mainspring drum 2 is located at the center of the case, and the hour wheel 48, attached to the hour hand 54 for displaying a single time, is located at the center of the watch dial.

Figure Labels

1. Watch movement

2. Wind-up drum

4. Spring shaft

6. Clock spring

6a. First external coil

6b. The final internal coil

8. Upper gear train

9. Upper bar

10. Clockwork box ratchet

12. Final Gear System

14. The First Final Round

16. Central pinion

18. Center wheel

20. Central motion device

22. The third pinion

24. Third round

26. Third motion device

28. The second pinion

30. Second round

32. Second motion device

34. Escapement pinion

36. Escape wheel

38. Escapement mechanism

40. Speed regulating components

42. Balance wheel

44. Gossamer threads

46. Anchor escapement fork

48. Hourly Wheel

50a. First bridge plate

50b. Second bridge plate

52a, 52b. Gems

54. Hour Hand

56. Friction wheel

58. Flexible arm

60. Protruding ears

62. Opening

Claims (4)

1. A watch mechanism comprising: a mainspring drum (2) mounted to pivot freely about a mainspring shaft (4); a mainspring barrel spring (6) housed within the mainspring drum (2), the mainspring barrel spring (6) comprising a first outer coil (6a) and a final inner coil (6b), the mainspring barrel spring (6) being attached to the mainspring drum (2) via the first outer coil (6a) and to the mainspring shaft (4) via the final inner coil (6b), the mainspring barrel spring (6) being wound by a winding lever (9) engaging with the mainspring drum (2) via a winding gear train (8); a mainspring barrel ratchet (10) fixedly mounted on the mainspring shaft (4), the watch mechanism further comprising a final gear train (12), the final gear train (12) being... The system (12) includes a first final wheel (14) that engages with the mainspring barrel ratchet (10) and transmits driving force from the mainspring drum (2) to the escapement (38) for the purpose of maintaining the oscillation of the regulating member (40), which regulates the timekeeping of the watch mechanism by oscillation. The watch mechanism also includes an hour wheel (48) that is frictionally mounted on the mainspring shaft (4), and an hour hand (54) is attached to the hour wheel (48) for displaying a single time. The hour wheel (48) is frictionally connected to the mainspring shaft (4), and the entire kinematic chain extending from the mainspring barrel ratchet (10) to the escapement (38) is calculated such that the mainspring barrel ratchet (10) and therefore the hour wheel (48) rotate at a rate of 12 or 24 hours per full revolution. 2. The clock mechanism according to claim 1, characterized in that the minute wheel is attached to the shaft of a wheel of the final gear train (12), the final gear train being calculated such that the minute wheel rotates a full revolution in 60 minutes. 3. The watch mechanism according to claim 1 or 2, characterized in that the hour wheel (48) is connected to the mainspring shaft (4) by means of a friction wheel (56) disposed between the mainspring drum (2) and the hour wheel (48), the friction wheel (56) being provided with two flexible arms (58) that clamp the mainspring shaft (4), such that the friction wheel (56) is elastically connected to and rotated by the mainspring shaft (4), the hour wheel (48) being placed on the friction wheel (56) such that two lugs (60) standing on the surface of the friction wheel (56) engage in two corresponding openings (62) formed in the hour wheel (48), which ensures the rotational connection between the hour wheel (48) and the friction wheel (56). 4. A clock, comprising a clock mechanism according to any one of claims 1 to 3.