Patent Publication Number: US-9841734-B2

Title: Timepiece display mechanism with a fast corrector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a National phase application in the United States of International patent application PCT/EP2015/057673 filed Apr. 09, 2015 which claims priority on European patent application 14168333.4 of May 14, 2014. The entire disclosures of the above patent applications are hereby incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention concerns a display mechanism for timepieces, comprising a fast position correction mechanism for a display wheel set. 
     The invention also concerns a timepiece movement including at least one display mechanism of this type. 
     The invention also concerns a timepiece or watch comprising at least one such movement and/or at least one such display mechanism. 
     The invention concerns the field of timepiece display mechanisms, and more specifically, comprising fast correction mechanisms. 
     BACKGROUND OF THE INVENTION 
     This invention concerns watches which require a fast (day, month or other) correction mechanism for certain functions, in particular display functions such as a calendar (annual, perpetual, day/date, or other), or moon phase, tide, AM/PM display or other indicators. A particular example of an annual calendar mechanism is described in Patent No EP1666991B1 in the name of ETA SA. 
     To set the month, the user generally has to make a correction using the calendar mechanism. In the worst case, this operation may prove time-consuming and tedious. It may be that a correction of a whole year has to be made. Likewise, if the user makes a mistake during correction, the operation has to be repeated. Using the calendar mechanism to operate the correction mechanism may lead to excessive use and could result in malfunctions. 
     Correction mechanisms often include levers, which are essential components in timepiece movements, enabling a mechanism to switch between several different modes, in general between two distinct positions. A return spring is often provided with a timepiece lever to ensure proper motion transmission or continued bins depending on the case. 
     A fast correction of the month display may result in desynchronization of the system. The user then has no means of checking whether the system is synchronized, which may lead to malfunctions. 
     SUMMARY OF THE INVENTION 
     The invention proposes to prevent such desynchronization of a calendar or date mechanism, and enables the calendar mechanism to self-synchronize. 
     The present invention proposes to overcome the aforementioned drawbacks of the prior art and to prevent any desynchronization of the mechanism. 
     To this end, the invention concerns a timepiece display mechanism according to claim  1 . 
     The invention also concerns a timepiece movement comprising at least one such display mechanism. 
     The invention also concerns a timepiece or watch comprising at least one such movement and/or at least one such display mechanism. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the invention will appear upon reading the following detailed description, with reference to the annexed drawings, in which: 
         FIG. 1  shows a partial perspective schematic view of a watch comprising a display mechanism according to the invention, in the particular application to an annual calendar mechanism. 
         FIG. 2  represents a detail of  FIG. 1  with fast calendar correction means illustrated in two different positions. 
         FIG. 3  shows a schematic plan view of a watch movement comprising a calendar mechanism with a fast automatic correction mechanism according to  FIG. 1 . 
         FIG. 4  shows a set of schematic cross-sections passing through the pivot axes of the main wheel sets;  FIG. 4A  represents the cooperation between an intermediate wheel set and a particular date ring comprised in said calendar mechanism;  FIG. 4B  shows the cooperation of a safety lever according to the invention with the date ring and with the intermediate wheel, in a position in which the intermediate wheel is properly synchronized;  FIG. 4C  shows the cooperation of a fast correction mechanism with the data ring and with the intermediate wheel. 
         FIG. 5  shows a schematic perspective view of a detail similar to  FIG. 1 , in a position of cooperation between a safety lever specific to the invention and a date ring. 
         FIG. 6  shows a schematic perspective view, similar to  FIG. 1 , of the same mechanism in an ordinary date ring driving position. 
         FIG. 7  shows a schematic, perspective view of a particular date ring specific to the invention. 
         FIGS. 8 to 11  show partial plan schematic views of the annual calendar mechanism of the preceding Figures, equipped with a month disc carried by a month-star, and a date indicator ring carried by the date ring, in four successive positions changing to 29th July, to 30th July, to 31st July and to 1st August. 
         FIG. 12  is a block diagram representing a watch comprising a movement cooperating with a display mechanism according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The invention concerns the field of timepiece mechanisms, and more specifically control and motion transmission mechanisms. It finds preferred application in the correction and updating of display mechanisms, and more specifically in display mechanisms  500  comprising a fast correction mechanism  200 , controlled by the user, via control means  17 , such as a stem or similar. 
     A display mechanism  500  is conventionally driven by an automatic drive mechanism controlled by a movement  1000  comprised in timepiece  2000 , notably a watch, in which is integrated display mechanism  500 . In normal operation, the kinematic chain of the display mechanism, via a drive means  1 , ensures the periodic driving of at least one display wheel set  3 . Preferably, the periodic driving is accomplished directly by a wheel set  1 C downstream of a gear train driven by movement  1000 , preferably arranged to complete one revolution in twenty-four hours. 
     Timepiece display mechanisms generally comprise at least one freely mounted wheel set, which is held in position by a friction spring, or by elastic return means, such as a jumper spring or suchlike. 
     A fast correction mechanism  200  generally includes means arranged to uncouple the automatic drive mechanism, and to replace at least one wheel set of the kinematic chain of said automatic drive mechanism with at least one other wheel set arranged to drive, directly or indirectly, at least one display wheel set  3 , and thereby effect a change of position of said display wheel set. 
     The invention proposes to improve such a mechanism to make desynchronization of the assembly impossible. 
     According to the invention, fast correction mechanism  200  comprises, in immediate proximity to display wheel set  3 , at least one intermediate wheel set  6 , which pivots in normal mode in a single direction S. According to variants, intermediate wheel set  6  may, on different parallel stages, fulfil different functions. 
     At the very least, the intermediate wheel net ensures, on a first stage  61 , synchronization with display mechanism  500 : the angular orientation of intermediate wheel set  6  with respect to the automatic drive mechanism of the display mechanism is then correct. 
     According to the invention, inserted between intermediate wheel set  6  and display wheel set  3 , display mechanism  500  comprises a safety lever  400 , also called the synchronization lever. 
     This safety lever  400  is arranged to be driven by display wheel set  3 , when display wheel set  3  is periodically driven, in a determined trajectory and with a travel that interferes with the spatial volume of intermediate wheel set  6 . The relative arrangement of safety lever  400  and intermediate wheel set  6 , which are mounted to pivot about distinct parallel axes, is such that:
         when intermediate wheel set  6  is correctly synchronized, the trajectory of safety lever  400  does not interfere with a first intermediate wheel set located on a first stage  61  of intermediate wheel set  6 , and safety lever  400  is arranged to pass at a distance from any other surface of intermediate wheel set  6 , without interfering with intermediate wheel set  6 ;   when the intermediate wheel set  6  is not correctly synchronized, the trajectory of safety lever  400  interferes with the first intermediate wheel set on first stage  61  of intermediate wheel set  6 , and safety lever  400  is arranged to drive intermediate wheel set  6  in the opposite direction R to the single normal operation direction S, to resynchronize intermediate wheel set  6 .       

     In the particular and non-limiting variant illustrated by the Figures, intermediate wheel set  6  is arranged to ensure:
         on a first stage  61 , synchronization with the automatic drive means of display mechanism  500 ;   on a second stage  62 , the direct or indirect driving of a display wheel set other than first display wheel set  3 .       

     The relative arrangement of intermediate wheel set  6  and safety lever  400  is then such that:
         when intermediate wheel set  6  is correctly synchronized the trajectory of safety lever  400  does not interfere with the first intermediate wheel set on first stage  61  of intermediate wheel set  6 , and safety lever  400  is arranged to pass above and at a distance from a second intermediate wheel set located on second stage  62  of intermediate wheel set  6 , without interfering therewith;   when the intermediate wheel set  6  is not correctly synchronized, the trajectory of safety lever  400  interferes with the first intermediate wheel set on first stage  61  of intermediate wheel set  6 , and safety lever  400  is arranged to drive intermediate wheel set  6  in the opposite direction R to the single normal operation direction S, to resynchronize intermediate wheel set  6 .       

     The first intermediate wheel set on first stage  61  and the second intermediate wheel set on second stage  62  are integral in rotation. In a particular embodiment, intermediate wheel set  6  is in one-piece. 
     In both cases, the travel of safety lever  400  is complete when display wheel set  3  ceases driving said lever. Safety lever  400  is advantageously equipped with elastic return means  403 , which tend to permanently return it to a rest position, which is the start of cooperation position, in the next period, with display wheel set  3 . 
     Preferably, intermediate wheel set  6  comprises a first intermediate wheel on first stage  61  and a second intermediate wheel set on second stage  62 . 
     The first intermediate wheel comprises teeth alternating with other teeth comprised in the second intermediate wheel. Advantageously, in projection on a plane, the teeth of the first intermediate wheel and those of the second intermediate wheel have the same profile, and some of them are aligned. More specifically, the first intermediate wheel comprises half as many teeth as the second intermediate wheel; the teeth are identical and one out of two is aligned. Consequently, the aligned teeth extend in double thickness on first stage  61  and on second stage  62 , whereas the teeth of the second intermediate wheel which have no corresponding tooth on the first intermediate wheel only extend on second stage  62 . In the particular variant illustrated, the second intermediate wheel includes ten teeth, and the first intermediate wheel has five. 
     Preferably, safety lever  400  comprises a blade portion  404  which only extends on the first stage. This blade  404  comprises a stop surface  402  arranged to repel the toothing of the first intermediate wheel set at first stage  61  in the event of desynchronization. On the opposite side with respect to a pivot axis B, lever  400  preferably has a beak  401 , arranged to cooperate with display wheel set  3 , to drive safety lever  400  via said display wheel set. 
     In a more specific embodiment, intermediate wheel set  6  also includes, on a third stage which does not interfere with safety lever  400 , a third toothed wheel  63 . This third toothed wheel  63  is then arranged to mesh, directly or indirectly, with another display wheel set. 
     The invention is more particularly illustrated, in a non-limiting manner, for the advantageous application wherein display mechanism  500  is a calendar mechanism  300 , comprising a data drive wheel set  1 , arranged to be controlled by a wheel of a timepiece movement  1000  and arranged to control a year wheel  4 . At least one said display wheel set  3  is a date ring, and calendar mechanism  300  comprises control means arranged to drive, directly or indirectly, said at least one date ring  3 . Calendar mechanism  300  further comprises a fast date correction mechanism  200 , which is arranged to control, directly or indirectly, the pivoting of said date ring  3 . 
       FIG. 7  illustrates a particular variant of date ring  3  which comprises three functional toothings  33 ,  34 ,  35 , disposed on different superposed levels, here in three parallel planes. In this particular variant, fast correction mechanism  200  thus comprises one such intermediate wheel set  6  including the following, which are integral and arranged on parallel levels:
         on a first upper level  30 , a first intermediate wheel  61  arranged to cooperate, either with safety lever  400  which is also arranged to cooperate, on the same level, with fingerpieces  33  comprised in date ring  3 , or with a month-star  5  mounted for free rotation on year wheel  4 ;   on a second intermediate level  31 , a second intermediate wheel  62  arranged to cooperate, at the end of each month, with a lug  35  comprised in date ring  3 ;   on a third lower level  32 , date ring  3  is arranged to be driven by date drive wheel set  1 ; a third intermediate wheel  63 , integral and coaxial with the first intermediate wheel on first stage  61  and with the second intermediate wheel on second stage  62 , is arranged to cooperate with year wheel  4 , and an intermediate corrector wheel  12  comprised in fast date correction mechanism  200  is arranged to cooperate with the second intermediate wheel on second stage  62  for correction of the month.       

     More particularly, this calendar mechanism  300  further comprises, on a fourth level underneath third lower level  32 , a corrector fingerpiece  14 , comprised in fast date correction mechanism  200 , and which is arranged to cooperate with teeth  34  located on lower level  32  of date ring  3 , for correction of the date. 
     Date ring  3  may either be made in one-piece or with juxtaposed elements indexed with respect to each other. 
     A particular application of the invention concerns an annual calendar mechanism  300  as described in EP Patent No 1666991B by the same Applicant. Display wheel net  3  is described here, in a non-limiting manner, in the form of a date ring, arranged to carry at least one date indicator ring, not represented in the Figures This date ring may be, in a known manner, retained by a jumper spring in order to achieve a semi-instantaneous change. 
     This annual calendar mechanism  300 , which may take the form of a module added to a mechanism of an existing movement, is arranged to be driven by a wheel  1 C, for example an hour wheel, of a movement  1000 , not represented in detail in the Figures, and which may equally well be a mechanical movement or an electronic movement. 
     This annual calendar mechanism  300  thus includes a date indicator drive wheel  1 , which is equipped with two fingerpieces:
         a first day fingerpiece  1 A arranged to drive once per day, notably at midnight, a toothing comprising thirty-one inner teeth  34 , on a lower level  32  of a date ring  3 ;   a second month fingerpiece  1 B arranged to drive, at the end of months of less than thirty-one days, a cam  2  arranged coaxially to a year wheel  4 .       

     This cam  2  comprises five radially protruding secondary lugs  2 E which correspond to the months of less than thirty-one days: February, April, June, September, November, and which are angularly distributed as a function of the time interval between these respective months: 60°, 60°, 90°, 60°, 90°. Cam  2  is clear between these secondary lugs  2 E, which means that the second month fingerpiece  12  only drives cam  2  on the last days of these particular months, the month of February requiring an additional manual correction, depending on the year. 
     Cam  2  is integral with a year wheel  4 . 
     In the preferred embodiment illustrated by the Figures, this year wheel  4  comprises twenty-four teeth. It may be arranged to carry, in some variant embodiments, a month indicator disc or ring, not represented in the Figures. 
     In a particular variant, as seen in the Figures, year wheel  4  may carry a month-star  5 , which rotates freely. Month-star  5  may be arranged to carry, in some variant embodiments, a month indicator ring or disc, not represented in the Figures. 
     At the end of each month, intermediate wheel set  6  is arranged to connect year wheel  4  to a main lug  35  located on a second intermediate level  31  of date ring  3 . 
     Intermediate wheel set  6  comprises a second intermediate wheel  62 . At the end of each month, regardless of the duration of the month, this second intermediate wheel  62  drives main lug  35 . 
     Intermediate wheel set  6  cooperates, via a third intermediate toothed wheel  63  on a third lower level  32 , with year wheel  4 . 
     Intermediate wheel set  6  comprises, in the alignment of first upper level  30 , a first intermediate wheel on first stage  61 , integral with the second intermediate wheel of second stage  62 . In the illustrated variant, the first intermediate wheel of first stage  61  cooperates with month-star  5  which is mounted for free rotation and held by friction. 
     In the illustrated variant, the first intermediate wheel of first stage  61  and third toothed wheel  63  each comprise ten equidistant teeth. 
     At the end of the months of less than thirty-one days, the second month fingerpiece  1 B of date indicator drive wheel  1  drives cam  2 , and year wheel  4  consequently drives, on the one hand, drive wheel set  6  and data ring  1  by means of its lug  35 , and on the other hand, month-star  5 . 
     At the end of the months of thirty-one days, the change from the thirty-first to the first occurs naturally, as does the change of month. 
     Date ring  3  comprises a particular arrangement, since it includes twenty-nine fingerpieces  33 , located on an upper level  30  parallel to lower-level  32  where the thirty-one teeth  34  are arranged. These fingerpieces  33  are arranged to cooperate with an external beak  401  of safety lever  400 , opposite to bearing face  402  comprised in safety lever  400 , to push the toothing of first intermediate wheel  61  in the event of desynchronization. 
     The single main lug  35  of date ring  3  extends at least over the top of the second intermediate wheel of second stage  62 . Consequently, on the thirtieth and thirty-first of the month, the system cannot lose synchronization, since main lug  35  is still meshed with intermediate wheel set  6 . 
     At the end of the other days of the month, when date ring  3  effects its movement, one of the twenty-nine fingerpieces  33  drives safety lever  400 , to ensure, if necessary, synchronization of the system, as explained above. 
       FIG. 7  shows the relative arrangement of the date ring levels. The toothing of twenty-nine fingerpieces  33 , on upper level  30 , is a toothing of thirty-one equidistant teeth from which two consecutive teeth have been removed. On second intermediate level  31 , main lug  35  is positioned here between the second and third fingerpieces  33  which follow the tooth-free space located on upper level  30 . 
     The toothing located on first upper level  30  is thus used only to enable synchronisation; its teeth are active and drive lever  400 . Whereas the ordinary driving of date ring  30  is accomplished by toothing  4  comprising teeth  3 , on third lower level  32 . 
     Preferably, calendar mechanism  300  comprises at least one fast correction mechanism  200 , which includes one or more corrector fingerpieces  12  or  14 , arranged to change the angular position of an intermediate wheel set  6 , and/or to act directly on the position of a display member, such as a disc or a ring, carrying a date, month, day, year, leap year or other ring. In the particular example illustrated by the Figures, fast correction mechanism  200  comprises a lever  100 , pivoting about a first fixed axis D 1 , and which carries on a second axis D 2 , which is parallel to first axis D 1 , an output wheel set which comprises at least two stages and carries, on two different planes, at least a corrector fingerpiece  14  and a corrector intermediate wheel  12 , which are arranged to change the position of a date wheel set or of a date correction wheel set, and of a month display member or of a month display correction wheel set. More specifically, corrector fingerpiece  14  cooperates with date ring  3  for correction of the date, and intermediate corrector wheel  12  cooperates with the second intermediate wheel of second stage  62  for correction of the month. 
     The invention also concerns a timepiece movement  1000  including an hour wheel driving at least one such calendar mechanism  300 . 
     The invention also concerns a timepiece  2000 , in particular a watch, including at least one such movement  1000  and/or at least one such display mechanism and/or one such calendar mechanism  300 . 
     The invention provides novel security in the employment of a display mechanism with a fast correction function. Indeed, the user has no means of checking whether or not the system is synchronized. The invention enables the display mechanism, notably the calendar mechanism, to self-synchronize. 
     Naturally, the example of an annual calendar set out above is non-limiting, and those skilled in the art will know how to transpose it to other similar applications.