NO20211186A1

NO20211186A1 - Wristwatch with an improved date wheel system

Info

Publication number: NO20211186A1
Application number: NO20211186A
Authority: NO
Inventors: Mads Bøhn
Original assignee: Maturitas As
Priority date: 2021-10-04
Filing date: 2021-10-04
Publication date: 2023-04-05
Also published as: WO2023057373A1

Description

Wristwatch with an improved date wheel system.

FIELD OF THE INVENTION

The present invention relates to a date wheel system of a wristwatch with limited date wheel disc diameter.

BACKGROUND OF THE INVENTION

Wristwatches wearable on a human arm is common. Besides keeping track of time, it is common to provide other functions like a stopwatch etc. Another common function is a date window displaying the date of a day. Other more advanced date windows may display the name of a day together with the numerical date of the day, etc.

A location of a date display window is on a defined section of a watch dial enabling a visual contact with imprinted digits on a date wheel disc representing the date of the present day. For example, the date display window may be arranged on a lefthand side adjacent to an hour mark in an edge zone of the watch dial representing for example three o ́clock. One problem may be that a passing of an analogue watch hand of a watch, for example the hour hand may hide the date when passing over the date display window. When the hour hand is pointing towards the three o ́clock mark the date display window can be completely covered. The movement of for example the hour hand is relatively slow thereby hiding the displayed date during a period which some may experiences to be too long or inconvenient.

A date wheel as known in prior art is for example a circular shaped disc having the digits 1-31 imprinted around an edge zone of the circular shaped date wheel. The date wheel is moved around by the clock mechanism inside the watch body.

Above the date wheel on the watch dial an opening can be arranged representing the date display window. The date wheel is positioned such that the imprinted digits representing dates are visible through the date display window. Once every 24 hours, for example at midnight, the date wheel is moved forwards one position(i.e., next date) by for example a Geneva mechanism as known in prior art.

An hour hand and minute hand as well as a second hand are normally connected in a center point on a watch dial of analogue watches wherein respective drive shafts are protruding out from the watch dial. Respective watch hands are driven by the watch mechanism inside the watch body. The drive shafts may for example be arranged as a cylinder-shaped shaft inside another cylinder-shaped shaft etc. At respective ends of the drive shafts protruding upwards through the watch dial the respective watch hands are connected to corresponding drive shafts. Inside the watch body the respective drive shafts are connected to the watch mechanism.

Therefore, the location in prior art of a date wheel is normally in an area between the centrally located drive shafts and the periphery of the watch dial since a date wheel need a substantial diameter to be able to have thirty imprinted digits (1-31) around the edge zone area. These considerations are also valid for analogue watch hand watches when the shape of a watch dial is not circular but are embodied with different shapes like rectangles, elliptic shapes etc.

An example of a date wheel is disclosed in CH 310559A wherein two date wheel discs are arranged side by side. A first date wheel has imprinted the digits 0-3 while a second date wheel has imprinted the digits 0-9. The first date wheel represents the most significant digit of a date while the second date wheel represents the least significant digit of a date. A drive mechanism moves the first and second date wheel such that a correct date is displayed each day at a point where a periphery of the two date wheel discs meets. A possible problem using two date wheels arranged side by side is that the edge zone of the date wheel disc having the digits 0-3 has a shorter disc diameter than the date wheel disc having the digits 0-9 in the edge zone. When the date wheel with the least significant digit shifts for example from nine to zero the date wheel disc with the most significant digit (0-3) should move one digit forward. When using a mechanical watch mechanism, the different size of the diameters of the respective two date wheels may be a technical challenge when implementing the movement forward of the most significant digit date wheel disc relative to the other date wheel disc. CH 310559A disclose arranging the two date wheel discs with a same diameter and the digits 0-3 on the most significant date wheel disc is repeated once, i.e., eight digits (0-3 followed by 0-3) is imprinted around the edge zone of the most significant date wheel disc. A consequence of using two larger date wheel discs side by side with a same diameter is that the two discs dictates a minimum diameter of a watch dial that is at least twice the diameter of the respective date wheel discs. With reference to CH 310559A, Figure 1 illustrates the situation.

There are also different types of watch mechanisms, for example mechanical watches driven by a pull-up spring and electrical quarts watches. However, if the watch uses analogue watch hands indicating time, the same problem with a date display window being covered by for example an hour hand is probably present regardless of the type of watch mechanism that is inside the watch body and the possible consequence of a larger watch dial diameter.

There is one location on a watch dial any watch hand never will cover when moving around, and that is the center position of the watch dial. This location is normally occupied by the respective drive shafts of the respective watch hands. Further, arranging two date wheel discs of a same diameter side by side having a date display window in the center of a watch dial increases the diameter of the watch dial since the respective peripheries of the two adjacent date wheel discs meets in the center of the watch dial.

A larger or smaller watch dial diameter is not only an aspect of design and appearance. A watch diameter of a wristwatch must be adaptable to different sizes, for example between watches for women or men or for children. Therefore, it is beneficial to have a date wheel disc arrangement that do not impose larger watch dial diameters. A further aspect is that the digits imprinted on a date wheel must have a minimum size to be readable by a human.

Therefore, there is a need of an improved date display mechanism for a wristwatch capable of displaying a date in a date display window located at a center position of a watch dial wherein the date wheel system minimizes the total diameter of the date wheel system.

OBJECT OF THE INVENTION

It is a further object of the present invention to provide an alternative to the prior art.

In particular, it may be seen as an object of the present invention to provide a date wheel mechanism of a wristwatch with smaller date wheel disc diameter as well as limited height of the date wheel mechanism.

SUMMARY OF THE INVENTION

Thus, the above-described object and several other objects are intended to be obtained in a first aspect of the invention by providing a date wheel system comprising two date wheels wherein one date wheel is located on top of the other date wheel rotating around a same centered rotation point.

The invention is particularly, but not exclusively, advantageous for obtaining a An analogue wristwatch with a date wheel system comprising

- a first date wheel disc comprising imprinted digits from zero to nine in an edge zone area of the first date wheel disc, and

- a second date wheel disc comprising imprinted digits from zero to three in an edge zone area of the second date wheel disc,

- wherein the second date wheel disc is mounted on top of the first date wheel disc such that the first date wheel disc and the second date wheel disc are rotatable around a common rotation point in the center of each respective date wheel disc, wherein a diameter of the second date wheel disc is less than the diameter of the first date wheel disc.

Respective aspects of the present invention may each be combined with any of the other aspects. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described herein.

DESCRIPTION OF THE FIGURES

The date wheel mechanism according to the present invention will now be described in more detail with reference to the accompanying figures. The attached figures illustrates an example of embodiment of present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

Figure 1 disclose an example of embodiment of the present invention.

Figure 2 disclose further details of the the example of embodiment disclosed in Figure 1.

Figure 3a disclose further details of the example of embodiment disclosed in Figure 1.

Figure 3b disclose further details of the example of embodiment disclosed in Figure 1.

Figure 4a disclose further details of the example of embodiment disclosed in Figure 1.

Figure 4b disclose further details of the example of embodiment disclosed in Figure 1.

DETAILED DESCRIPTION OF AN EMBODIMENT

Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Further, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention.

Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.

Figure 1 disclose an example of embodiment of the present invention. A watch 10 comprises a watch dial 11 arranged with a date display window 12 in the center of the watch dial 11. Around the date display window 12 there is arranged for example three cylinder shaped drive shafts 13, one inside the other, connected to a respective watch hand 14 indicating hour, a respective watch hand 15 indicating minutes and a respective watch hand 16 indicating seconds.

Figure 2 indicates a possible location 17 of a date wheel disc arranged inside the watch body and below the watch dial 11 surface. The radius of the watch dial 11 is indicated by the reference numeral 17a. If all digits 1-31 are imprinted on a single date wheel disc the diameter of the date wheel disc will extend somewhat longer than the indicated radius 17a of the watch dial 11 to be able to display imprinted date digits in the center position of the watch dial. If two adjacent date wheels are arranged side by side as known in prior art (refer CH 310559A), the diameter of the respective discs are smaller in diameter since less digits are needed (i.e., 0-9) to be imprinted on the respective date wheel discs. However, as discussed above, the diameter of the watch dial is at least twice the sum of the respective two date wheel disc diameters, and as discussed above the two date wheel discs are often of a same diameter.

Figure 3a disclose an example of a date wheel arrangement according to the present invention. Figure 3a illustrates the date wheel discs seen from above. A least significant date wheel disc 18 has the digits 0-9 imprinted on an outer area of the edge zone of the disc 18. A most significant date wheel disc 19 (digits 0-3) is arranged on top of the date wheel disc 18 and both discs are rotated around a common rotating point 20. At a defined location 21 the respective numbers on the two date wheel discs will be aligned and indicates the date the date wheel arrangement is displaying. The position of the digit “zero” on the most significant date wheel disc 18 is optional and the position can be left without an imprinted digit “zero”. Instead of displaying a date “02” for example the date is displayed as only “2”.

Figure 3b illustrates a cross sectional view of the example illustrated in Figure 3a. The least significant date wheel disc 18 is arranged with an indent in the surface enabling positioning the most significant date wheel disc 19 inside the indent on the surface of the least significant date wheel disc 18. A date wheel drive shaft 20a passes through another date wheel drive shaft 20b through the common rotating point 20. The drive shaft 20a is connected to an upward faced surface inside the indent on the surface of the least significant date wheel disc 18. The drive shaft 20b is connected to an upward faced surface of the most significant date wheel disc 19. However, it is also possible to have the respective drive shafts 20a, 20b connected to surfaces of the least significant date wheel disc 18 and the most significant date wheel disc 19 facing downwards. The drive shafts would then protrude outwardly from the bottom surface of the least significant date wheel disc 18. Which configuration that is utilized can be due to other factors regarding other parts of a watch mechanism used with the date wheel system according to the present invention.

The respective Figures 3a and 3b are not representing actual dimensions of a date wheel system and is only to be viewed as an illustration of some principles of a date wheel system according to the present invention. For example, the distance between the two date wheel discs 18, 19 can be made close to zero thereby making the thickness of the date wheel system according to the present invention to be in the order of the thickness of the respective two date wheel discs. Further, the diameter of the date wheel disc is only defined by the most significant date wheel disc 18.

Figure 4a illustrates some features of an example of drive shafts 13 according to the present invention. The drive shafts 13 comprises three cylinder shaped drive shafts 13a, 13b, 13c arranged inside each other. The drive shaft 13a has the longest length of the three drive shafts. The drive shaft 13a is hollow and therefore it is possible to look through the drive shaft 13a from the top end to the bottom end as illustrated with the arrows in Figure 4a. The drive shafts 13 are protruding outwardly above a watch dial surface 11 when mounted. In the protruding part of the drive shafts 13 above the watch dial 11 respective watch hands can be mounted. For example, drive shaft 13a is connected to a second hand 16, drive shaft 13b is connected to a minute hand 15, and drive shaft 13c is connected to an hour hand 14.

The part of the drive shafts 13 located below the watch dial 11, i.e., inside a watch body or casing, may be arranged with a cogwheel pattern on the respective outer surfaces of each respective drive shaft 13a, 13b, 13c. A set of three cogwheels 22 mounted on a common shaft 23 can be in operational contact with the respective cogwheel patterns on the outer surface of the drive shafts 13a, 13b, 13c. However, each respective cogwheel may be operated independently.

A first drive shaft can be positioned and supported by a second drive shaft arranged inside the first drive shaft by for example locking rings fastened on the outer surface of the second drive shaft. For example, with reference to Figure 4a, drive shaft 13b may be supported by a locking ring on the outer surface of drive shaft 13a etc.

The respective drive shafts rotate independently inside each other. Therefore, low friction in between respective surfaces facing each other should be low. Therefore, smooth surfaces are preferable. A known technique is to use ceramic materials which can have low Roughness Average (Ra). For example, it is known that SiN (Silicon Nitride) materials can be made with an Ra of 0,01 μm. Such materials are also durable and is an option to use in examples of embodiments of the present invention.

Figure 4b is an example of a wristwatch 10 according to the present invention. The date wheel discs 18, 19 as illustrated in Figure 3a and 3b is embodied inside a watch body 10. The watch body has an outer surface 28 made of glass and a watch dial 11 inside the watch body is located above the watch mechanism. The watch mechanism. The rectangle 26 indicates a watch time mechanism, for example a mechanical watch mechanism as known in prior art that controls the movement of the respective watch hands 14, 15, 16. The three cogwheels 22 is therefore in mechanical contact via the watch time drive connection 26a with the watch time mechanism 26. An adjustment knob 27 is arranged protruding outside the watch body and in contact with the watch time mechanism 26 enabling adjustment of the time displayed by the watch.

On an opposite side of the watch time mechanism 26 a watch date mechanism 24 is arranged being in mechanical contact (reference numeral 30) with the watch time mechanism 26. I this manner control of a date displayed by the date wheel discs can be done from the watch mechanism 26. A further possibility to adjust the date can be done via a knob 25 arranged on an outside surface of the watch body.

The respective drive shafts 21a, 21b of the two date wheel discs are connected to the watch date mechanism 24 via a watch date drive 29.

The date reading position 21 illustrated in figure 4a of the date wheels 18, 19 is positioned just below the opening of the inner drive shaft 13a.

The rotation of the respective date wheel discs 18, 19 is dependent on each other’s relative position. For example, when the least significant date wheel disc 18 shifts from the digit “nine” to the digit “zero” the most significant date wheel disc 19 should move one position forward, for example form the digit “two” to the git “three”. Such correlated and controlled movements may be implemented with a known Geneva drive mechanism. This mechanical solution is one of the most used design for producing intermittent rotary motion.

The dimensions of the example of embodiment of a watch 10 according to the present invention as depicted in Figure 4b is not accurate with respect to actual possible dimensions but illustrates only some key feature of respective embodiments of the present invention.

An aspect is the example of embodiment illustrated in Figure 4b is that not only the diameter of the watch dial 11 can be embodied as a smaller watch dial but also that the height of the watch body can be limited. For example, the positioning of the watch date mechanism 24 above the center of the two date wheel discs fills a space defined by the height of the drive shaft 13a protruding downwards from the watch dial 11. Since the height of the two date wheel discs 18, 19 also is limited as discussed above, the height of the total watch date system is limited. The watch time mechanism 26 is also possible to make as a thinner mechanism as known in prior art.

Therefore, a wristwatch according to the present invention can be embodied with a smaller watch dial diameter and a limited height of a watch.

According to an example of embodiment of an analogue wristwatch 10 with a date wheel system comprises

- a first date wheel disc 18 with imprinted digits from zero to nine in an edge zone area of the first date wheel disc 19, and

- a second date wheel disc 19 with imprinted digits from zero to three in an edge zone area of the second date wheel disc 19,

- wherein the second date wheel disc 19 is mounted on top of the first date wheel disc 18 such that the first date wheel disc 18 and the second date wheel disc 19 are rotatable around a common rotation point 20 in the center of each respective date wheel disc 18, 19, wherein a diameter of the second date wheel disc 19 is less than the diameter of the first date wheel disc 18.

In the example of embodiment disclosed above, the second date wheel disc 19 may be positioned inside an indent on an upper surface of the first date wheel disc 18.

In the example of embodiment disclosed above, a first drive shaft 20a may be driving the first date wheel disc 18 and may be attached to a centered bottom point inside the indent on the surface of the first date wheel disc 18, and a second drive shaft 20b may be connected to a centered point on an upper surface of the second date wheel disc 19.

In the example of embodiment disclosed above the first drive shaft 20a may be arranged inside the second drive shaft 20b, wherein the first and second drive shaft 20a, 20b are arranged in the common rotation point 20.

In the example of embodiment disclosed above, a drive shaft 13 may comprise a first hollow cylinder-shaped drive shaft 13a arranged inside a second cylinder shaped drive shaft 13b, wherein the first and second drive shafts 13a, 13b are arranged inside a third cylinder shaped drive shaft 13c, wherein the respective drive shafts 13a, 13b, 13c are connected in one end to respective watch hands indicating seconds 16, minutes 15 and hours 14.

In the example of embodiment disclosed above, the rotation of the respective date wheel discs may be configured to display digits representing a date at a common date reading point 21 wherein the digit on the second date wheel disc 19 is aligned with the digit on the first date wheel disc 18.

In the example of embodiment disclosed above, the position of the digit zero on the most significant date wheel disc 19 is arranged without any imprint of a digit zero.

In the example of embodiment disclosed above, a watch body of the wristwatch 10 is arranged with the date wheel discs 18, 19 such that the date reading point 21 is located below the opening of the hollow drive shaft 13a.

In the example of embodiment disclosed above, a watch date mechanism 24 may be arranged above the date wheels 18, 19 and a watch date drive connection 29 is arranged between the drive shafts 21a, 21b of the date wheel discs 18, 1) and the watch date mechanism 24.

In the example of embodiment disclosed above, a watch time mechanism 26 may be arranged on a second side of the drive shafts 13 opposite the first side, wherein the respective drive shafts 13a, 13b, 13c are driven and controlled by the watch time mechanism 26.

In the example of embodiment disclosed above, a watch time date connection 30 may be arranged between the watch date mechanism 24 and the watch time mechanism 26 there by enabling a control of a displayed date from the watch time mechanism 26.

Reference numerals:

10 watch

11 watch dial

12 date display

13 watch hand-drives

13a watch hand drive for the second hand

13b watch hand drive for the minute hand

13c watch hand drive for the hour hand

14 hour hand

15 minute hand

16 second hand

17 location of date wheel

17a radius of date wheel

18 least significant date wheel

19 most significant date wheel

20a rotation axle of the least significant date wheel 20b rotation axle of the most significant date wheel 21 date view position of the date wheels

22 cogwheel drives of the watch hand-drive

23 rotation axis of the cogwheel drives

24 watch date mechanism

25 adjustment knob for the watch date mechanism 26 watch time mechanism

26a watch time drive connection

27 adjustment knob for the watch time drive

28 glass cover of the watch

29 watch date drive connection

30 watch time date connection

Claims

Claims:

1. An analogue wristwatch (10) with a date wheel system comprising

- a first date wheel disc (18) comprising imprinted digits from zero to nine in an edge zone area of the first date wheel disc (19), and

- a second date wheel disc (19) comprising imprinted digits from zero to three in an edge zone area of the second date wheel disc (19),

- wherein the second date wheel disc (19) is mounted on top of the first date wheel disc (18) such that the first date wheel disc (18) and the second date wheel disc (19) are rotatable around a common rotation point 20 in the center of each respective date wheel disc (18, 19), wherein a diameter of the second date wheel disc (19) is less than the diameter of the first date wheel disc (18).

2. The wristwatch of claim 1, wherein the second date wheel disc (19) is positioned inside an indent on an upper surface of the first date wheel disc (18).

3. The wristwatch of claim 2, wherein a first drive shaft (20a) driving the first date wheel disc (18) is attached to a centered bottom point inside the indent on the surface of the first date wheel disc (18), and wherein a second drive shaft 20b is connected to a centered point on an upper surface of the second date wheel disc (19).

4. The wristwatch of claim 3, wherein the first drive shaft (20a) is arranged inside the second drive shaft (20b).

5. The wristwatch of claim 1, wherein a drive shaft (13) comprises a first hollow cylinder shaped drive shaft (13a) arranged inside a second cylinder shaped drive shaft (13b), wherein the first and second drive shafts (13a, 13b) are arranged inside a third cylinder shaped drive shaft (13c), wherein the respective drive shafts (13a, 13b, 13c) are connected in one end to respective watch hands indicating seconds (16), minutes (15) and hours (14).

6. The wristwatch of claim 1, wherein the rotation of the respective date wheel discs is configured to display digits representing a date at a common date reading point (21) wherein the digit on the second date wheel disc (19) is aligned with the digit on the first date wheel disc (18).

7. The wristwatch of claim 6, wherein the position of the digit zero on the most significant date wheel disc (19) is arranged without any imprint of a digit.

8. The wristwatch according to claims 5 and 6, wherein a watch body of the wristwatch (10) is arranged with the date wheel discs (18, 19) on a first side of the drive shafts (13) such that the date reading point (21) is located below the opening of the hollow drive shaft (13a).

9. The wristwatch of claim 8, wherein a watch date mechanism (24) is arranged above the date wheels (18, 19) and a watch date drive connection (29) is arranged between the drive shafts (21a, 21b) of the date wheel discs (18,19) and the watch date mechanism (24).

10. The wristwatch of claim 8, wherein a watch time mechanism (26) is arranged on a second side of the drive shafts (13) opposite the first side, wherein the respective drive shafts (13a, 13b, 13c) are driven and controlled by the watch time mechanism (26).

11.The wristwatch of claim 10, wherein a watch time date connection (30) is arranged between the watch date mechanism (24) and the watch time mechanism (26) there by enabling a control of a displayed date from the watch time mechanism (26).