Permanent calendar mechanism with concentric cams

Abstract

Improve the structure of the perpetual calendar mechanism for a clock. 【Solution means】 The present invention relates to a mechanism for a clock movement comprising a set of concentric cams (20) provided with a monthly cam (22) and an annual cam (30). This mechanism further comprises a lever (50) having a contact portion (52) provided so as to cooperate with the set of concentric cams (20), and a star wheel (70). This star wheel (70) is provided with a lever (50) that further operates on the last day of a month with less than 31 days according to the angular positions of the monthly cam (30) and the annual cam (22), and is provided to operate daily directly or indirectly for calendar adjustment until the 1st day of the next month. The monthly cam (22) is provided with a radial opening (27), and the contact portion (52) of the lever (50) can cooperate with one or the other of the monthly cam (22) and the annual cam (3) according to the angular position of the monthly cam (22).

Description

Technical Field

[0001] The present invention relates to a perpetual calendar mechanism for a watch movement including a moon cam and an annual cam concentrically nested within the moon cam. The present invention also relates to a watch, particularly a wristwatch, including a watch movement equipped with a perpetual calendar mechanism having concentric cams.

Background Art

[0002] There are various mechanisms for displaying information related to the date. From relatively simple structures that display the date without correction, to the annual calendar type that can control the passage of a 30-day or 31-day month to the 1st of the next month, and the perpetual calendar type that incorporates a mechanical memory and can control not only the passage of a 30-day or 31-day month to the 1st of the next month but also the passage from the end of February to March 1st considering leap years.

[0003] Therefore, perpetual calendar mechanisms usually have a complex and cumbersome structure, and may have a significant impact on the size of the watch case incorporating a watch movement equipped with such a mechanism.

[0004] As an example, Patent Document 1 discloses a perpetual calendar mechanism based on a 48-cam with 48 notches, each notch being associated with the months of four consecutive years. This mechanism also includes a lever with a feeler tail (contact tail) intended to cooperate with these 48 notches.

[0005] Patent Document 2 discloses another example of a perpetual calendar mechanism. This mechanism includes a moon cam with an eccentric circular cutout, in which an annual cam is provided. A large lever is arranged to contact the contour of either the moon cam or the annual cam according to the respective angular positions of the moon cam and the annual cam. Since the annual cam is eccentric with respect to the moon cam, the perpetual calendar mechanism not only rotates the annual cam once every four years about its axis but also includes a drive system that rotates the annual cam once a year about the center of the moon cam.

[0006] This mechanism includes a drive system, and as a result, it has the disadvantage of being relatively complex in order to impart two different movements to the annual cam.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] Therefore, an object of the present invention is to provide a perpetual calendar mechanism that is at least free from the above limitations.

[0009] More specifically, an object of the present invention is to provide a compact perpetual calendar mechanism.

[0010] Another object of the present invention is to provide a perpetual calendar mechanism that is easier to construct, more robust, and thus more reliable.

[0011] Another object of the present invention is to provide a perpetual calendar mechanism provided with a drive system for the monthly and annual cams with reduced complexity compared to the above mechanism.

Means for Solving the Problems

[0012] These objectives are achieved, in particular, by a perpetual calendar mechanism for a watch movement comprising a set of concentric cams. This set comprises a month cam configured to be driven at a rate of one revolution per year and a year cam configured to be driven at a rate of one revolution every four years. The month cam has a central recess in which the year cam is disposed. The mechanism further comprises a lever having a contact portion configured to cooperate with the set of concentric cams and a star wheel. The star wheel is directly or indirectly actuated daily by the lever and is configured to catch up to a state corresponding to the 1st day of the next month by further actuating on the last day of a month with less than 31 days, depending on the angular positions of the month cam and the year cam. The month cam has a radial opening such that the contact portion of the lever can cooperate with either the month cam or the year cam depending on the angular position of the month cam.

[0013] In one embodiment, the thickness of one of the month cam and the year cam is at least half of the thickness of the other of the month cam and the year cam.

[0014] In one embodiment, the thickness of one of the month cam and the year cam is at least 3 / 5, preferably at least 4 / 5, of the thickness of the other of the month cam and the year cam.

[0015] In one embodiment, the upper side of the month cam is substantially in the same plane as the upper side of the year cam.

[0016] In one embodiment, the lower side of the month cam is substantially in the same plane as the lower side of the year cam.

[0017] In one embodiment, the central recess of the month cam comprises a cylindrical wall disposed relative to at least a part of the contour of the year cam so that the year cam can rotate and guide the month cam.

[0018] In one embodiment, the annual cam is fixed to a large wheel that engages with at least one wheel arranged to be driven by the star wheel once a month. The monthly cam is arranged to be driven by a gear train including a first wheel fixed to and coaxially mounted on the monthly cam, a second wheel that engages with the first wheel, and an intermediate wheel fixed to the second wheel and engaging with the teeth of the large wheel.

[0019] In one embodiment, the contact portion of the lever is arranged between the first wheel and the large wheel.

[0020] In one embodiment, the first wheel and the monthly cam are integrated to form one part.

[0021] In one embodiment, the large wheel and the annual cam are integrated to form one part.

[0022] In one embodiment, the contour of the annual cam has three radial notches corresponding to the section of February in a non - leap year of the cam.

[0023] In one embodiment, the mechanism further includes a 24H (24 - hour) wheel configured to be driven at a speed of one rotation in 24 hours, and a 24 - hour pawl fixed to the 24 - hour wheel. The lever includes, as a part thereof, a first beak arranged to cooperate with the 24 - hour pawl, and a second beak arranged to rotate a star wheel for 31 days typically fixed to the display of the day of the month.

[0024] In one embodiment, the mechanism further includes a wheel and a pawl fixed to the wheel. The lever includes a rack that engages with the wheel so that each time the lever is actuated by the pawl, the pawl engages with the star wheel for 31 days. In this way, the star for 31 days can rotate one step per day.

[0025] Another aspect of the present invention relates, on the one hand, to a timepiece movement comprising a calendar mechanism with a concentric cam according to the present invention, and on the other hand, to a timepiece, particularly a wristwatch, comprising a timepiece movement comprising a calendar mechanism with a concentric cam according to the present invention.

[0026] Examples of embodiments of the present invention are given in the description shown by the accompanying drawings.

Brief Description of the Drawings

[0027]

Figure 1

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Figure 10d

[0028] In a preferred embodiment, particularly referring to FIGS. 1 to 7, the perpetual calendar mechanism 10 includes a set of concentric cams 20 and a lever 50 provided to cooperate with the set of concentric cams 20 and operate the star wheels 31 to 70 according to the information provided by the set of concentric cams 20. This set 20 includes a month cam 22 generally known as a 12-month cam and a year cam 30 attached coaxially with the month cam 22.

[0029] For this purpose, the month cam 22 includes a central recess 28 defined by a cylindrical wall 28a and a radial opening 27 extending from an end of the cam contour and opening into the central recess 28, particularly as shown in FIGS. 5 and 6. The year cam 30 is provided inside the central recess 28 of the month cam. Preferably, this central recess 28 consists of a through-opening formed in the month cam 22. Also preferably, this opening is basically circular to allow the year 30 cam to pass through the month cam 22.

[0030] In FIGS. 6 and 7, the monthly cam has four sections 25a corresponding to months with 30 days in a year and seven sections 25b corresponding to months with 31 days in a year. Among them, two pairs of sections corresponding to the month pairs from July to August and from December to January are each formed by adjacent sections 25b. The sections 25a and 25b and the radial opening 27 representing the month of February are provided continuously so as to represent different months of the year in chronological order.

[0031] The radial opening 27 is, in this way, bounded by two sections 25b corresponding to January and March. The sections 25a and 25b are typically circular sections that define arcs with the same center at their distal ends. As will be described in detail below, the radial opening 27 enables the lever 50 to obtain information from the annual cam in order to adjust the star wheel 70 at the end of the month of February depending on whether the year is a leap year or not.

[0032] Referring to FIG. 7, the contour of the annual cam 30 has three radial notches 34a that are 90° apart from each other. These three notches are used for correcting the date display at the end of February in non - leap years. The contour of the annual cam 30 also has a section 34b that extends between two radially opposed radial notches 34a. The section 34b is used for correcting the date display at the end of February in leap years.

[0033] Preferably, the upper and lower sides of the monthly cam 22 and the annual cam 30 are flat and perpendicular to the common axis of rotation of these cams. Referring to FIG. 3, the upper side 23a of the monthly cam 22 is substantially in the same plane as the upper side 32a of the annual cam 30, that is, the deviation between the respective upper sides of the two cams does not exceed 20%, preferably 10% of the thickness of one of the cams. The same applies to the respective lower sides 23b and 32b of the monthly cam 22 and the annual cam 30. As a result, the monthly cam 30 is preferably integrally nested in the monthly cam 22 having a cam contour of a constant diameter facing the cylindrical wall 28a of the central recess 28, whereby the monthly cam can be rotationally guided by the annual cam.

[0034] However, the thickness of the monthly cam may be substantially different from the thickness of the annual cam in a plurality of embodiments not shown. The thickness of the monthly cam 22 may be much smaller than the thickness of the annual cam 30. And for example, it may be half of the thickness of the annual cam. Conversely, it is also possible, that is, the thickness of the annual cam 30 may be much smaller than the thickness of the monthly cam 22, and for example, it may be half of the thickness of the annual cam.

[0035] Advantageously, the cylindrical wall 28a defining the central depression 28 of the monthly cam 22 is arranged with respect to the contour of the cam of constant diameter of the annual cam 30. Preferably, this installation is made with just enough clearance so that one of the cams 22, 30 does not drag the other by friction. In this way, the annual cam can rotate at a speed of one revolution every four years while guiding the rotation around the contour of the monthly cam 22 at a speed of one revolution per year. Therefore, the monthly cam 22 and the annual cam 30 rotate non-connected and at different speeds.

[0036] Referring particularly to FIG. 4, the annual cam 30 is connected to the large wheel 36. This wheel typically meshes, as shown in FIG. 1, preferably with a gear train comprising a first wheel 37 and a second wheel 38. The first wheel 37 is provided so as to be driven once a month by a drive pawl 76 attached to the star wheel 70. This star wheel is fixed to a display (not shown) having numbers from 1 to 31 and can be continuously displayed, for example, through the clock face opening. The gear train 37, 38 drives the large wheel 36 to rotate once every four years to drive the annual cam 30, so that the annual cam 30 rotates once every four years.

[0037] The large wheel 36 and the annual cam 30 are made as a single part, but can be made as separate parts and one can be fixed to the other. The monthly cam 22 is provided to be driven by a gear train including a monthly cam 22 mounted coaxially as a part thereof, a first wheel 42 connected thereto, a second wheel 44 meshing with the first wheel 42, and an intermediate wheel 46 connected to the second wheel 44 and meshing with the teeth of the large wheel 36. Similar to the large wheel 36 and the annual cam 30, the monthly cam 22 and the first wheel 42 are made as a single part, but can also be made as separate parts and one can be fixed to the other.

[0038] In FIG. 1, the second wheel 44 has 12 teeth and cooperates with a jumping spring 47 to drive the monthly cam 22 by the second wheel 44 that rotates at a speed of one jump every 30° (1 / 12 revolution) per month. The jumping spring 47 completes the jump. The perpetual calendar mechanism 10 also includes a 24-hour wheel 80 provided to be driven at a speed of one revolution per day. The 24-hour pawl 82 is fixed to the 24-hour wheel 80, actuates a lever 50, and the lever then rotates a star wheel 70 via a pawl 66 connected to a wheel 62. The wheel 62 connected to the lever 50 is rotated so that the star wheel 70 makes one jump per day and meshes with a rack 58 (rack) connected to the lever 50. In addition, if necessary, adjustments are made at the end of the month according to the angular positions of the monthly cam 22 and the annual cam 30.

[0039] Referring to FIG. 2, the lever 50 is provided with a contact portion 52 (feeler 52) made to cooperate with the contour of one or both of the annual cam and the monthly cam and the other contour as a function of the respective angular positions of each cam for this purpose. In particular, the contact portion 52 is made to abut against the contour of any of the aforementioned cams. Since they are arranged at different radial distances from the common rotation center of the cams 22 and 30, these different contours allow for a change in the amplitude of the movement of the lever when the lever 50 is actuated by the pawl 82.

[0040] As shown in FIG. 3, the contact portion 52 is disposed between the first wheel 42 and the large wheel 36. In this figure, the radial opening 27 of the lunar cam 22 is disposed opposite the contact portion 52 such that the contact portion is introduced into this opening and contacts the contour of the annual cam 30 so as to be able to perform the correction necessary at the end of February in consideration of leap years.

[0041] The lever 50 further includes a first beak 54 disposed on the track of the 24-hour claw 82 and a second beak 56 provided to operate the star wheel 70 by a catch claw 72 connected to the star wheel 70. The star wheel 70 cooperates with a jumping spring 74 as shown in FIG. 1. Note that the catch claw 72 is attached to a leaf spring 73 provided to bend under the action of the second beak 56 of the lever. Thereby, when the contact portion 52 retracts with respect to the set of concentric cams 20, the lever 50 is not blocked by this claw.

[0042] For example, a helical lever spring 60 is fixed to the wheel 62 to bias the wheel 62 to the angular position shown in FIG. 1. In particular, this arrangement including the brake 58, the wheel 62, and the lever spring 60 enables the contact portion 52 of the lever 50 to be biased against the contour of one or the other of the lunar cam 22 and the annual cam 30 when the lever is stationary. The claw 66 is fixed to the wheel 62 to operate the star wheel 70 once a day, that is, one step. Note that FIG. 1 shows the state of the mechanism on February 28th, which is not a leap year.

[0043] Since the catch claw 72 is fixed to the star wheel 70, it rotates once a month. This claw is disengaged from the track of the second beak 56 of the lever 50 throughout the month, ensuring that the lever operates the star wheel 70 daily only by the claw 66, thus ensuring the transition from the display of one day to the display of the next day. At the end of each month with less than 31 days, the catch claw 72 is disposed on the track of the second beak 56 of the lever 50, particularly as shown in FIG. 1.

[0044] When the pawl activates the lever 50 again, the latter drives the star wheel 70 by the action of the second beak 56 on the catch pawl 72 as a function of the amplitude of the movement of the lever 50, which is directly linked to the respective angular positions of the month and year cams 22, 30. The star wheel 70 makes one or more additional jumps in order to perform a catch-up (calendar adjustment) during the night from the last day of a month of less than 31 days to the 1st day of the following month.

[0045] Instead of using a conventional 48-cam (a cam with 48 conventional notches), using an annual cam nested within a monthly cam advantageously makes the contact part larger in size, consequently enabling a more robust structure. This increases the reliability of the perpetual calendar mechanism and makes it less susceptible to the effects of manufacturing defects. It also enables easier assembly and adjustment of the perpetual calendar mechanism.

[0046] Here, the operation of the perpetual calendar mechanism 10 will be described with reference to FIGS. 1 and 8a to 10d.

[0047] FIGS. 1 and 8a to 8d represent a series of operations at the end of February in a non-leap year. As described above, FIG. 1 shows the state of the mechanism on February 28th in a non-leap year. At this point, a part of the lateral edge of the contact part 52 is positioned relative to the edge of the radial opening 27 of the monthly cam. The distal part of the contact part 52 is inside one of the notches 34a of the annual cam 30 (FIG. 7).

[0048] FIG. 8a shows the mechanism when the pawl 82 contacts the first beak 54 of the lever 50 and applies a thrust to the lever to release the contact part 52 from the radial notch 34a of the annual cam. Next, the second beak 56 of the lever 50 applies a thrust to the catch pawl 72 of the star wheel 31, causing the star wheel to start rotating.

[0049] The movement of the second beak 56 shown between the representations of FIGS. 8a and 8b enables the rotation of the star wheel 70 by the catch pawl 72. As a result, this star wheel makes three consecutive jumps. Therefore, the amplitude of the movement of the lever 50 is maximum during this period.

[0050] When the lever 50 moves, its rake rotates the wheel 62, which, as shown in FIGS. 8c and 8d, gradually rotates the pawl 66 until the star wheel 70 is moved in one step. Thus, on the night from February 28th of a non - leap year to March 1st, the second beak 56 of the lever 50 activates the star wheel 70 so that it makes three consecutive jumps, after which the pawl 66 activates the star to make additional jumps.

[0051] Referring to FIG. 8c, it should be noted that when the star wheel 70 activates at the end of this month, the first wheel 37 can be driven via the drive pawl 76. The first wheel drives the large wheel 36 to rotate one - forty - eighth of a revolution via the second wheel 38. This rotation also rotates the year cam 30 one - forty - eighth of a revolution and the month cam 22 one - twelfth of a revolution via the gear train that constitutes the first wheel 42, the second wheel 44, and the intermediate wheel 46. For the month of 31 days, in this case the section 25b of the month cam corresponding to March is in the path of the contact part 52 of the lever, as seen in FIG. 8d. Once the pawl 82 is released from the first beak 54 of the lever, the contact part 52 is returned to the section 25b under the action of the helical spring 60.

[0052] From March 1st, the catch pawl 72 is released from the path of the beak 56 of the lever 50 throughout the month, and only the pawl 66 activates the star wheel 70 every day, thus ensuring the passage from the display of one day to the display of the next day. By the contact of the contact part 52 of the lever with the section 25b of the month cam, especially at the end of the month passing through the period from March 30th to 31st, the lever 50 can be arranged so that the second beak 56 is released from the path of the catch pawl 72. Thus, no correction is made for this month. The same applies to all months with 31 days, such as March.

[0053] Figures 9a and 9b show a series of operations at the end of February in a leap year. Figure 9a shows the mechanism on the 29th day. The contact portion 52 of the lever 50 is arranged with respect to the section 34b of the contour of the annual cam at this time. During the night from the 29th to March 1st, the 24-hour claw 82 applies a thrust to the first beak 54 of the lever 50, and the second beak 56 applies a thrust to the catch claw 72 (Figure 9b) of the star wheel 70 to drive the star wheel until it jumps continuously twice. Next, the claw 66 operates the star wheel 70 as described above, and the star wheel makes additional jumps to change the display from the 29th to March 1st.

[0054] Figures 10a to 10d show a series of operations at the end of April. Figure 10a shows the mechanism on April 30th. The contact portion 52 of the lever 50 is arranged with respect to the section 25a of the contour of the monthly cam at this time. The claw 82 applies a thrust to the first beak 54 of the lever 50 as shown in Figure 10b, and then the second beak 56 of the lever drives the star wheel 70 through the catch claw 72 as shown in Figure 10c. Therefore, the star wheel jumps under the action of the claw 66 that is rotated by the action of the brake of the lever on the wheel 62 and then makes additional jumps.

[0055] It can be seen from Figure 10b that when the star wheel 70 operates at the end of this month, the first wheel 37 is driven through the drive claw 76. As described above, the gear trains 37, 38 that connect the star wheel 70 to the large wheel 36 and the gear trains 44, 46 that connect the large wheel 36 to the first wheel 42 enable the monthly cam to be driven by a 1 / 12 rotation. The section 25b of the monthly cam corresponding to the 31st day of the month, in this case May, is therefore on the track of the contact portion 52 of the lever. In Figure 10d, when the claw 82 is released from the first beak 54 of the lever, the contact portion 52 is pressed against the section 25b under the action of the helical spring 60.

[0056] The series of operations described above in relation to April is the same for other months that have 30 days like April.

[0057] Various changes can be made to the above-described calendar mechanism without departing from the invention described in the claims. For example, the lever 50 can be shaped to directly operate the star wheel 31 every day. The star wheel can, in particular, make a single jump independently of the amplitude of the movement of the lever, which thereby makes it possible to eliminate, for example, the need for the pawl 66. In another variant, the lever can be replaced by a conventional large lever provided with a large click (switching member) that cooperates with a cam 31 fixed to the star wheel 31 instead of the catch pawl.

Explanation of Signs

[0058] Permanent calendar mechanism 10 Concentric cam set 20 Month cam 22 Upper side 23a Lower side 23b Interval 25a of a 30-day month Interval 25b of a 31-day month Radial opening 27 Central depression 28 Cylindrical wall 28a Year cam 30 Upper side 32a Lower side 32b Radial notch 34a Interval 34b Large wheel 36 Gear train First wheel 42, second wheel 44 Intermediate wheel 46 Jumping spring 47 Gear train First wheel 37, second wheel 38 Lever 50 Contact part 52 First beak 54 Second beak 56 Brake 58 Lever spring 60 (helical spring for example) Wheel 62 Pawl 66 From star wheel 31 to 70 Catch pawl 72 Leaf spring 73 Jumping spring 74 Drive pawl 76 24-hour wheel 80 24-hour claw 82

Claims

1. A lunar cam (22) having a central recess (28) and arranged to be driven at a speed of one revolution per year, and A year cam (30) located in the central recess (28) of the lunar cam (22) and made to be driven to rotate once every four years A set of concentric cams (20) comprising A lever (50) provided with a contact part (52) arranged to cooperate with the set of concentric cams (20), A star wheel (70) which is made to operate directly or indirectly by the lever (50) every day and is further operated on the last day of a month with less than 31 days according to the angular positions of the lunar cam (22) and the year cam (30) for calendar adjustment, In a perpetual calendar mechanism (10) for a watch movement, comprising The lunar cam (22) has a radial opening (27), and the contact part (52) of the lever (50) can cooperate with one or the other of the lunar cam (22) and the year cam (30) according to the angular position of the lunar cam (22). A perpetual calendar mechanism (10) for a watch movement.

2. The thickness of one of the lunar cam (22) and the year cam (30) is at least half of the thickness of the other of the lunar cam (22) and the year cam (30). The mechanism (10) according to Claim 1.

3. The thickness of one of the lunar cam (22) and the year cam (30) is at least 3 / 5, preferably at least 4 / 5 of the thickness of the other of the lunar cam (22) and the year cam (30). The mechanism (10) according to Claim 1 or 2.

4. The upper side (23a) of the lunar cam (22) is substantially in the same plane as the upper side (32a) of the year cam (30). The mechanism (10) according to any one of Claims 1 to 3.

5. The lower side (23b) of the lunar cam (22) is substantially in the same plane as the lower side (32b) of the year cam (30). The mechanism (10) according to any one of Claims 1 to 4.

6. The central recess (28) of the lunar cam (22) comprises a cylindrical wall (28a) arranged with respect to at least a part of the contour of the year cam (30), so that the year cam (30) can guide the rotation of the lunar cam (22). The mechanism (10) according to any one of Claims 1 to 5.

7. The annual cam (30) is fixed to a large wheel (36) that engages with at least one wheel (37, 38) provided to be driven by the star wheel (70) once a month. The monthly cam is provided to be driven by a gear train including a first wheel (42) fixed to and coaxially mounted on the monthly cam, a second wheel (44) that engages with the first wheel (42), and an intermediate wheel (46) fixed to the second wheel (44) and engaging with the teeth of the large wheel (36). The mechanism (10) according to any one of claims 1 to 6.

8. The contact portion (52) of the lever (50) is provided between the first wheel (42) and the large wheel (36). The mechanism (10) according to claim 7.

9. The first wheel (42) and the monthly cam (22) are integrated to form one part. The mechanism according to claim 7 or 8.

10. The large wheel (36) and the annual cam (30) are integrated to form one part. The mechanism according to any one of claims 7 to 9.

11. The contour of the annual cam (30) includes three radial notches (34a) corresponding to the non-leap-year intervals of the cam. The mechanism (10) according to any one of claims 1 to 10.

12. The mechanism further includes a 24-hour wheel (80) adapted to be driven at a speed of one revolution in 24 hours, and a 24-hour pawl (82) fixed to the 24-hour wheel (80). The lever (50) includes a first beak (54) provided to cooperate with the 24-hour pawl (82), and a second beak (56) that drives the star wheel (70) to rotate via a catch pawl (72) fixed to the star wheel (70). The mechanism (10) according to any one of claims 1 to 11.

13. The mechanism further includes a wheel (62) and a pawl (66) fixed to the wheel (62). Each time the lever (50) is actuated by the 24-hour pawl to engage the pawl (66) with the star wheel (70), the lever (50) includes a brake (58) that engages with the wheel (62). The mechanism (10) according to claim 12.

14. A watch movement comprising the mechanism according to any one of claims 1 to 13.

15. A timepiece, particularly a wristwatch, comprising the watch movement according to claim 14.

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