US-12625471-B2 - Leap-year display mechanism for a horological movement with a perpetual calendar display

Abstract

A leap-year display mechanism for a horological movement with a perpetual calendar display including a drive element connected to a month wheel set rotated by one step per month, a transmission star intended to be attached to a structure of the horological movement, arranged along the stroke of the drive element so as to be rotated thereby when the month wheel set completes one full revolution, a leap-year display connected to the transmission star via a reduction gear train so that with each revolution of the month wheel set, the leap-year display is rotated by one step.

Inventors

• Christophe RIEDO
• Jean-Philippe Rochat

Assignees

• MONTRES BREGUET S.A.

Dates

Publication Date

20260512

Application Date

20231026

Priority Date

20221109

Claims (6)

1. 1 . A leap-year display mechanism for a horological movement with a perpetual calendar display, wherein the display mechanism comprises: a drive element connected to a month wheel set rotated by one step per month; a transmission star configured to be attached to a structure of the horological movement, arranged along the stroke of the drive element so as to be rotated thereby when the month wheel set completes one full revolution; a leap-year display connected to the transmission star via a reduction gear train so that with each revolution of the month wheel set, the leap-year display is rotated by one step, wherein the leap-year display includes a roller comprising a display wall on which indications representative of the current type of year are shown, including a leap year and normal years, wherein the drive element comprises a finger attached eccentrically to the month wheel set by a mechanical connection, and wherein the drive element projects from a side face of the month wheel set in a direction along a longitudinal axis of the month wheel set and in a direction of the leap-year display.
2. 2 . The display mechanism according to claim 1 , wherein the transmission star has four teeth.
3. 3 . The display mechanism according to claim 1 , wherein the leap-year display comprises an annular bearing surface by which the leap-year display is attached to the reduction gear train, said annular bearing surface being connected to the display wall with an end wall.
4. 4 . The display mechanism according to claim 3 , wherein the leap-year display comprises a mechanism for adjusting the angular position thereof, formed by a radial lug attached to the annular bearing surface, via which said annular bearing surface is connected to the end wall, said radial lug comprising a threaded hole cooperating with a screw engaged in an oblong hole made in the end wall and extending in a curvilinear direction.
5. 5 . The display mechanism according to claim 1 , wherein the reduction gear train comprises a first wheel rigidly attached coaxially to the transmission star for rotation therewith, and a second wheel rigidly attached coaxially to the leap-year display for rotation therewith.
6. 6 . The display mechanism according to claim 1 , wherein the reduction gear train is configured such that one step of the leap-year display corresponds to one eighth of a revolution.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to European Patent Application No. 22206485.9 filed on Nov. 9, 2022, the entire disclosure of which is hereby incorporated herein by reference. TECHNICAL FIELD OF THE INVENTION The invention relates to the horological field, and in particular to timepieces with a perpetual calendar display. More particularly, the invention relates to a leap-year display mechanism for a horological movement with a perpetual calendar display. TECHNOLOGICAL BACKGROUND Perpetual calendar display mechanisms are well known horological complications allowing a date to be displayed, which perpetual calendar display mechanisms allow the date to be displayed by adapting automatically, i.e. without the need for manual intervention, to the length of the month, in particular while taking leap years into account. In some timepieces, the perpetual calendar display mechanism is connected to a display indicating whether the current year is a leap year or a normal year. These mechanisms are complex to produce and assemble. Moreover, they typically consume a lot of power. SUMMARY OF THE INVENTION The invention overcomes the aforementioned drawbacks by providing a solution for displaying leap years that is relatively simple in design and has minimal power consumption. The mechanism according to the invention is particularly suitable for a roller display. To this end, the present invention relates to a leap-year display mechanism for a horological movement with a perpetual calendar display comprising: a drive element connected to a month wheel set rotated by one step per month,a transmission star intended to be attached to a structure of the horological movement, arranged along the stroke of the drive element so as to be rotated thereby when the month wheel set completes one full revolution,a leap-year display connected to the transmission star via a reduction gear train so that with each revolution of the month wheel set, the leap-year display is rotated by one step. In specific embodiments, the invention can further include one or more of the following features, which must be considered singly or according to any combination technically possible. In specific embodiments, the drive element takes the form of a finger attached eccentrically to the month wheel set by a mechanical connection of the embedded type. In specific embodiments, the transmission star has four teeth. In specific embodiments, the leap-year display comprises indications representative of the current type of year, including a leap year and normal years. In specific embodiments, the leap-year display takes the form of a roller comprising a display wall on which the indications representative of the current type of year are shown. In specific embodiments, the leap-year display includes an annular bearing surface by which it is attached to the reduction gear train, said annular bearing surface being connected to the display wall by means of an end wall. In specific embodiments, the leap-year display includes a mechanism for adjusting the angular position thereof, formed by a radial lug attached to the annular bearing surface, by means whereof said annular bearing surface is connected to the end wall, said radial lug comprising a threaded hole cooperating with a screw engaged in an oblong hole made in the end wall and extending in a curvilinear direction. In specific embodiments, the reduction gear train includes a first wheel rigidly attached coaxially to the transmission star for rotation therewith and a second wheel rigidly attached coaxially to the leap-year display for rotation therewith. In specific embodiments, the reduction gear train is configured such that one step of the leap-year display corresponds to one eighth of a revolution thereof. BRIEF DESCRIPTION OF THE FIGURES Other features and advantages of the invention will become apparent upon reading the following detailed description given by way of a non-limiting example, and with reference to the accompanying drawings, wherein: FIG. 1 shows a partially exploded, perspective view of a leap-year display mechanism of a horological movement with a perpetual calendar display according to a preferred example embodiment of the invention; FIG. 2 shows a sectional view of a feature of the display mechanism in FIG. 1; FIG. 3 shows a sectional view along the cutting plane A-A in FIG. 2; FIG. 4 shows a sectional view along the cutting plane B-B in FIG. 2. It should be noted that the figures are not necessarily drawn to scale for clarity purposes. DETAILED DESCRIPTION OF THE INVENTION As can be seen in the exploded view in FIG. 1, the invention relates to a leap-year display mechanism 10 for a horological movement with a perpetual calendar display. The leap-year display mechanism 10 comprises a month wheel set rotated by one step per month, to which a drive element 21 is connected. In the preferred embodiment of the invention, the drive element 21 advantageo