Patent Publication Number: US-2021173344-A1

Title: Timepiece display mechanism with an instantaneous jump function

Description:
FIELD OF THE INVENTION 
     The invention concerns a timepiece display mechanism with an instantaneous jump function, arranged to be driven by a timepiece movement, and comprising a stop work mechanism of the Maltese cross type with a control wheel set able to control, in part of its angular travel, the pivoting of at least one planet wheel set. 
     The invention also concerns a timepiece, particularly a watch, including at least one such display mechanism. 
     The invention concerns the field of display mechanisms for timepieces with complications. 
     BACKGROUND OF THE INVENTION 
     The use of Maltese cross stop work mechanisms is known for certain display functions in watchmaking. The best known is the leap year display on a perpetual calendar timepiece. 
     Usually, a Maltese cross mechanism is said to be a continuous drive mechanism. The planet wheel rotates continuously around a sun wheel, and the rotation of the planet wheel on its own axis is also slow and continuous. 
     Continuous displays create uncertainty for the user, especially around the time of the display change, because he does not have means of knowing whether or not the display change has taken place. 
     Patent No. WO2010/058367A1 in the name of BALLOUARD discloses a watch display mechanism, the movement of which drives a cannon-pinion, at the free end of which is attached an indicator member performing one revolution per hour above a dial provided with twelve or twenty-four markings indicating the hours in a circular arrangement. These markings are each connected to an isolated pinion, provided with an even number of teeth, driven simultaneously with one of its adjacent pinions by meshing with a toothed sector whose pitch diameter is equal to half the number of markings multiplied by the pitch diameter of the pinion, and which is rotated, around said cannon-pinion after each revolution of the indicator member, by an angular value equal to one revolution divided by the number of markings, by control means, which are driven in turn by the rotation of the cannon-pinion. 
     Swiss Patent No. CH3366A in the name of JACCARD discloses a watch, known as a ‘handless watch’ comprising a combination of a cannon-pinion carrying a cam and a wheel and a disc/finger designed to actuate a Maltese cross wheel. This disc carries one of the ends of a spiral spring, the other end of which is attached to the cannon-pinion or to the arbor carrying the latter, and a tooth or lower protuberance passing through an aperture in the wheel, in combination with a lever or arm having a tooth or protuberance and with a spring; the tooth or protuberance temporarily stopping the disc/finger during the continuous rotation of the cannon-pinion, and leaving it to its own devices as soon as the tooth or protuberance drops into the cam notch. 
     SUMMARY OF THE INVENTION 
     The invention proposes to make the jump of a Maltese cross mechanism instantaneous. 
     The invention also proposes to make a display mechanism for a timepiece, particularly a watch, implementing at least one planet wheel set having a specific movement. More particularly, this specific movement includes at least one phase of continuous rotational movement of the planet wheel set about an element called the sun wheel and at least one phase of isolated and instantaneous rotational movement of the planet wheel set on itself, at a precise place and time. 
     The invention consists in making the one-off rotation of the planet wheel about its axis instantaneous, while ensuring its rotation about the sun wheel, without changing the rotational speed of the planet axis around the sun wheel. 
     To this end, the invention concerns a timepiece display mechanism according to claim  1 . 
     The invention also concerns a timepiece, particularly a watch, including 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  schematically represents the specific movement of a planet wheel set about an element called the sun wheel; the planet wheel set is in continuous rotational movement (arrows A) about the sun wheel, and, in at least one angular position, performs a pivoting movement on itself (arrow B), this pivoting movement may be partial or total depending on the arrangement of the mechanism; 
         FIG. 2  shows a schematic, partial and plan view of one portion of an instantaneous jump display mechanism according to the invention, showing only the constituent elements of a drive mechanism, from a gear train of a timepiece movement, of a star whose arms carry these planet wheel sets, consisting here of planet wheels, each comprising a partially truncated toothing, and each arranged to slide over a cylindrical portion of an annular ring guided on annular ringannular ring rollers, or to mesh with an outer toothed portion of this annular annular ringring, depending on the angular position of the planet wheel concerned; this star rotates continuously here, in a non-limiting manner, on star rollers, and rotates here in the clockwise direction; 
         FIG. 3 a    is a plan view of a detail of  FIG. 2  showing such a planet wheel in its sliding position on the cylindrical portion of the annular ringannular ring; 
         FIG. 3 b    represents the same detail in perspective. 
         FIG. 4  represents, in a similar manner to  FIG. 2 , another portion of the same instantaneous jump display mechanism according to the invention, in which only the constituent elements of a drive mechanism are shown, from a gear train of a timepiece movement and through a cam wheel set and then a driver, of the annular ringannular ring with which the planet wheels cooperate, this drive mechanism being represented in an activated position of the annular ringannular ring, the arrow indicates the anti-clockwise direction in which the annular ring will pivot as soon as a feeler of this driver, which follows a snail cam of this cam wheel set, falls, this pivoting movement driving in rotation the planet wheel which then appears opposite the outer toothed portion of the annular ring; 
         FIG. 5  is a detail of  FIG. 4 , showing the cam wheel set which includes, coaxial and superposed on each other: a friction wheel, a plate, and a snail cam, the friction wheel adjustably driving the plate which includes a slot for limiting and driving an eccentric finger comprised in the snail cam, on which moves the driver feeler, which is a pivoting rack here, comprising a rack toothing arranged to cooperate with a annular ring toothing; 
         FIG. 6  represents, in a similar manner to  FIG. 4 , the same drive mechanism represented in the deactivated position of the annular ring: the arrow indicates the clockwise direction, in which the annular ring is ready to pivot subsequently, relative to the instant illustrated in  FIG. 6 , in the anti-clockwise direction, when the same feeler rises to the highest point of the snail cam 
         FIG. 7  is, in a similar manner to  FIG. 5 , a detail of  FIG. 6 ; 
         FIG. 8  represents a schematic, partial plan view of the entire instantaneous jump display mechanism, in which the star drive mechanism and the annular ring drive mechanism are combined, to ensure both the orbital movement of the planet wheels with respect to a plate of the movement, and the instantaneous rotational movement of each planet wheel when it appears opposite the outer toothed portion of the annular ring and just before the instant when this annular ring moves in an instantaneous jump from its activated position to its deactivated position. 
         FIGS. 9 to 15  represent, in a similar manner to  FIG. 3 , the successive steps of the kinematics of a planet wheel: 
         FIG. 9  represents the approach position of the planet wheel which is on the right of the Figure, and which is sliding in the clockwise direction, whereas the planet wheel visible on the left has just rotated and thus resumes a sliding travel; the annular ring is in the activated position; 
         FIG. 10  represents the pre-jump position; the planet wheel arrives in position at six o&#39;clock; the annular ring is still in the activated position; 
         FIGS. 11 to 14  show a breakdown of the jump: 
       in  FIG. 11 , the planet wheel is still in position at six o&#39;clock, the annular ring is currently rotating in the anti-clockwise direction, it is in the process of changing from the activated position to the deactivated position; 
       in  FIG. 12 , the annular ring continues its anticlockwise travel and meshes with the planet wheel, and starts to rotate the latter; 
       in  FIG. 13  this synchronised double movement continues; 
       in  FIG. 14 , the synchronised double movement is completed, the last tooth of the planet wheel leaves the outer toothing of the annular ring to present the truncated part of the planet wheel toothing opposite the cylindrical track of the annular ring; 
       in  FIG. 15 , in its post-jump position, the planet wheel has finished its instantaneous rotation of a half-turn on itself; the planet wheel, driven by the star, leaves the six o&#39;clock position and will resume its sliding movement on the cylindrical track of the annular ring; the annular ring then returns from its deactivated position to its activated position, but this movement occurs more slowly than the advance of the star, so as not to interfere with the operation in progress with the planet wheel, but with the appropriate lag to be ready to cause the instantaneous jump of the next planet wheel, which will appear an hour later in the six o&#39;clock rotation position in this particular and non-limiting embodiment; 
         FIG. 16  represents a schematic plan view, seen from the opposite side of the movement to that of all the preceding Figures, of the cam wheel set which includes a friction wheel which is driven, via a motion work wheel set, by the cannon-pinion, and which friction drives a pivot of the plate, and is mounted coaxial with the plate and the cam, and the angular adjustment of which with respect to the plate allows precise adjustment of the instant of jump of the annular ring; 
         FIG. 17  represents a perspective view of the cam wheel set from the same side; 
         FIG. 18  represents an exploded perspective view of the cam wheel set from the same side; 
         FIG. 19  represents a schematic plan view of a timepiece, consisting of a watch, comprising this display mechanism. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  sets out the general problem of the orbital movement of a planet wheel set about a fixed or movable element called the sun wheel, where the planet wheel set is in continuous rotational movement (arrows A) about the sun wheel, and, in at least one angular position, represented here in a non-limited manner at six o&#39;clock, makes a pivoting movement on itself (arrow B), the angular travel of this pivoting movement depending on the arrangement of the mechanism. 
     The invention is illustrated here in a particular variant with a single point of rotation of the planet wheels, but it is understood that a particular display mechanism can comprise several such rotation points spread over the periphery of the sun wheel, depending on the desired display application. 
     The invention concerns a timepiece display mechanism  100  with an instantaneous jump function. This display mechanism  100  is arranged to be driven by a timepiece movement, and comprises a stop work mechanism of the ‘Maltese cross’ type with a control wheel set  200  able to control, in at least part of its angular travel, the pivoting of at least one planet wheel set  300 . 
     According to the invention, this control wheel set  200  comprises a annular ring  10 , which is arranged to be pivoted indirectly from a driver wheel set or a cannon-pinion  12  comprised in a timepiece movement, via a cam wheel set  456 . 
     This cam wheel set  456  is arranged to move annular ring  10  from an activated position to a deactivated position by an instantaneous displacement of annular ring  10  in a first direction in order to pivot a planet wheel set  300  about a planet wheel axis, and to move annular ring  10  from the deactivated position to the activated position by a controlled displacement of annular ring  10 , slower than the instantaneous displacement, in a return movement in a second direction, opposite to the first direction. 
     Cam wheel set  456  comprises at least one plate  15  and one cam  16  which are coaxially mounted. Plate  15  is driven indirectly by cannon-pinion  12 , and comprises a slot  151 , arranged to limit the travel of an eccentric finger  160  comprised in cam  16  and to drive said finger into a stop position at one end of the slot. The changing profile  161  of cam  16  controls the pivoting of a driver  17 , which is arranged to drive annular ring  10  between two extreme activation and deactivation positions. On the one hand, slot  151  thus allows a clear jump of driver  17  which interacts with cam  16  in the deactivation direction, and on the other hand, a longer reactivation time related to the relative travel of finger  160  and of slot  151 . The utility of the strip/finger system is that it makes possible an instantaneous drop of the feeler, which, when it falls, touches the smallest radius of the cam. 
     More particularly, control wheel set  200  comprises a first alternation of first sliding areas and first driving areas, and planet wheel set  300  comprises a second alternation of second clear areas and second driving areas. The second clear areas are each arranged to slide in turn over one of the first sliding areas of the control wheel set during part of the angular travel of control wheel set  200  corresponding to a rest position of planet wheel set  300 . And the first driving areas of control wheel set  200  are arranged, in some portions of the angular travel of control wheel set  200 , to cooperate with the second driving areas comprised in planet wheel set  300  to pivot planet wheel set  300  until a second clear area cooperates with a first sliding area in another rest position of planet wheel set  300 . 
     More particularly, driver  17  is a pivoting rack, which is returned by a rack spring  18 , and which comprises a rack toothing  170 , which is arranged to cooperate with an inner annular ring toothing  107  of annular ring  10 . This pivoting rack includes a feeler  171 , which is arranged to follow the profile of cam  16 . 
     More particularly, cam  16  is a snail cam with a changing external profile  161  in the shape of a snail and a front edge  162  allowing the jump. And the combination of slot  151  and finger  160  allows and limits the return of feeler  171  on the largest radius of cam  16 . 
     In a particular embodiment, this changing snail-shaped external profile  161  expands over the first 180° of the cam, and is followed by a concentric portion with zero change over the rest of the angular travel; thus the toothed annular ring, in the activated position, can wait for the planet wheel to arrive. Preferably, the ascent ramp is not too steep, to avoid any interference with the planet wheel that has just jumped. 
     Advantageously, front edge  162  includes a slope that allows the mechanism to be reversible, which is useful during an adjustment, such as time-setting, which may require a backward movement. 
     According to the invention, cam wheel set  456  also comprises a friction wheel  14 , which is mounted coaxially with plate  15  and cam  16 , and is driven directly or indirectly (for example via a motion work wheel set  13 ) by cannon-pinion  12 , and which is arranged to friction drive a pivot  152  of plate  15 , and the angular adjustment of which with respect to the plate allows precise adjustment of the instant of jump of annular ring  10 . 
     More particularly, annular ring  10  is annular and pivots, guided by annular ring rollers  19  that are eccentric with respect to its pivot axis. Guiding by rollers is, naturally, not exclusive, this is a particular and non-limiting case of a guidance system. 
     More particularly, display mechanism  100  comprises a star  4  carrying each planet wheel set  300 , which is mounted to pivot in a continuous pivoting movement in a single direction of pivoting and driven by a wheel set of the timepiece movement. This continuous movement of the star is a particular, non-limiting case: it is understood that, for example, during a time-setting operation or suchlike, the rotation may not be continuous; the same is true for the direction of rotation, which may also be reversed, particularly in the same example of a time-setting operation. 
     Preferably, the pivot axes of annular ring  10  and of star  4  coincide; more particularly, they are coaxial with the main pivot axis D of hour wheel  1  or cannon-pinion  12  of the timepiece movement. 
     In a variant, each planet wheel set  300  is mounted to pivot freely on an arm  7  or the periphery of star  4 . 
     In another variant, each planet wheel set  300  is mounted to pivot with friction in a housing comprised in an arm  7  or the periphery of star  4 . 
     In particular, each planet wheel set  300 , notably a planet wheel  8 , is mounted at the end  71  of an arm  7 , comprised in star  4 , and which, in a particular variant, is flexible. This end  71  of arm  7  can also comprise a bearing for guiding another wheel set meshing with planet wheel  8 . Planet wheel  8  can comprise a planet wheel hub  80 , guided in a bore of end  71  of arm  7 , or in a friction clamp comprised in end  71  of arm  7 , formed by a complementary flexible arm  72 . Planet wheel  8  can also include at least one flange  83  for axial limitation with respect to end  71  of arm  7 . 
     In the particular variant illustrated by the Figures, each planet wheel set  300  includes a truncated toothing comprising teeth  81 ,  811 ,  812 ,  813 ,  814 ,  815 ,  816 , which are arranged to cooperate with a toothed outer part  108  of annular ring  10 , particularly annular ring teeth  1802 ,  1804 , of annular ring  10  for the relative driving thereof. Annular ring  10  comprises recesses  1801 ,  1803 ,  1805  between its structure and teeth  1802  and  1804 . And each planet wheel set  300  comprises recessed areas  82 ,  821 ,  822  which form second clear areas, allowing planet wheel set  300  to slide over a smooth cylindrical shoulder  9  comprised in annular ring  10 . In the example illustrated by the Figures, the sliding occurs at teeth  811 ,  816  on the one hand, and  813 ,  814  on the other hand, of planet wheel set  300 , which are collateral to each second clear area. 
     In the example illustrated by the Figures, planet wheel sets  300  each comprise two second clear areas  821 ,  822 , which allow a 180° rotation of the planet wheel. It is evident that other embodiments are possible, for example three second recessed areas for a 120° rotation, or otherwise; likewise, these second recessed areas are not necessarily equidistant. 
     In another variant that is not illustrated, each planet wheel set  300  is a Maltese cross with arms each having a cylindrical hollow profile forming a second clear area, which is arranged to slide over a cylindrical shoulder  9  of annular ring  10 . The branches of this Maltese cross are separated in a conventional manner by recesses, which are arranged to cooperate with a finger, or a tooth, or suchlike, protruding from annular ring  10  for the relative pivoting thereof. 
     In yet another variant, which is not illustrated, the mechanism comprises a Maltese cross which works on an inner toothing. 
     In a particular embodiment, display mechanism  100  is a moon phase or moon age display. 
     In another particular variant, display mechanism  100  is a day/night display. 
     In another particular variant, display mechanism  100  is an AM/PM display. In another particular variant, display mechanism  100  is a universal time display. 
     In another particular variant, display mechanism  100  is a calendar, date, day or month or leap year display. 
     The invention also concerns a timepiece  1000  comprising a timepiece movement, which is arranged to drive at least one such display mechanism  100 . 
     According to the invention, this display mechanism  100  comprises a separate function for driving control wheel set  200  in a back-and-forth pivoting movement with a limited angular travel, and for the continuous pivoting in a single direction of a star  4  carrying each planet wheel set  300 . 
     More particularly, this timepiece  1000  is a watch. 
     The Figures illustrate a particular, non-limiting variant of the invention and detail its operation. 
     Display mechanism  100  is composed here of two sub-systems, which are combined with each other:
         a first mechanism concerns the driving of star  4 , which carries planet wheel  300 , or planet wheels  3000  in the present case: this mechanism is arranged to take information from the train of a mechanical or electromechanical timepiece movement, to achieve a reduction in rotational speed via gear train, transmission and rotational guidance;   a second mechanism concerns the driving of annular ring  10 , which carries the fixed Maltese cross tooth; this mechanism is arranged to take information from the train of a mechanical or electromechanical movement, to allow adjustment by using a friction system, to produce a jump through the use of a cam mechanism, transmission and rotational guidance.       

     The sub-system relating to the driving of star  4 , illustrated in  FIG. 2 , has the objective of rotating planet wheel sets  300 , here planet wheels  8 , at constant speed around a plate  5 . 
     To achieve this movement, the information is taken at the centre of a timepiece movement, in particular but not exclusively from an hour wheel  1  comprising a toothing  11 , this information is transmitted by a gear train, comprising, in particular, a gear reduction wheel set  2  with toothings  21  and  22  and an intermediate wheel  3 , to star  4 , via its inner toothing  43 . Star  4  pivots around plate  5  by means of star rollers  6  guiding a bore  46  of star  4  and makes one revolution in twelve hours in the clockwise direction in the particular case illustrated. Naturally, this revolution in twelve hours is a particular design illustrated by the Figures, and other time values can be chosen for other applications, without departing from the invention. More particularly, star  4  comprises an inner toothing  43  on an annular rim which pivots, guided by star rollers  6  that are eccentric with respect to the pivot axis of star  4 . Guidance by rollers is only a particular case illustrated by the Figures, other modes of guidance can be envisaged, such as rotary bearing guidance, or otherwise. This toothing  43  cooperates with toothing  32  of intermediate drive wheel  3 . 
     Star  4  has twelve arms  7  here, these are more particularly but not exclusively flexible arms, these arms  7  make it possible to form a pivot with each planet wheel  8 . Planet wheels  8  are driven in rotation around plate  5  by star  4 , and they are angularly guided most of the time by annular ring  10 , by the toothing of planet wheels  8  sliding against cylindrical outer surface  9  of annular ring  10 . 
     Each planet wheel  8  makes one complete rotation around plate  5  in twelve hours, but without rotating on itself. 
     The sub-system relating to the driving of annular ring  10  has the objective of managing the displacement and angular position of annular ring  10 . 
     Annular ring  10  moves from the activated to deactivated position in a rapid instantaneous movement and then returns to the activated position in a slow controlled movement. More particularly, the rise during return to the activated position changes at the beginning and is zero at the end. 
     To achieve these various movements of annular ring  10 , the information is, particularly but not exclusively, taken at the centre of the timepiece movement from a cannon-pinion  12  and is transmitted by a motion work wheel set  13  to a cam wheel set  456 . This cam wheel set  456  includes a friction wheel  14 , which thus has a constant rotational speed, and makes one revolution in an hour in the clockwise direction (in the Figures CW=clockwise). 
     Cam wheel set  456  has three stages: friction wheel  14 , a plate  15  and a cam  16  which carries an eccentric finger  160 . This cam  16  has the function of manoeuvring a driver, here a pivoting rack  17 , to move annular ring  10  in one or other direction. Friction wheel  14  drives plate  15  via the friction exerted, for example, on a tapered shoulder  152  of plate  15  by flexible strips comprised in friction wheel  14  which delimit a slot  140 . Plate  15  drives finger  160  of cam  16  via a slot  151  comprised in plate  5 , particularly a slot in the arc of a circle concentric to plate  15 . 
     The friction allows precise adjustment of the instant of jump of annular ring  10 , and slot  151  allows a clear jump of rack  17  which interacts with cam  16 . 
     Rack  17 , constrained by a rack spring  18 , takes the information from the periphery of cam  16 , and transmits it to annular ring  10  by the meshing of inner toothing  107  of annular ring  10  with rack toothing  170 . More particularly, annular ring  10  pivots about plate  5  by means of annular ring rollers  19  which guide a annular ring bore  119 . 
     Annular ring  10  thus makes an instantaneous jump from its activated position to its deactivated position (in the Figures ACW: anti-clockwise), and then slowly returns in the opposite direction (in the Figures CW: clockwise) to the activated position, and this cycle is periodically repeated, for example every hour in the mechanism illustrated by the Figures; naturally this periodicity depends on the type of display, and the period would be different for a moon age display, for example. 
       FIG. 4  shows the annular ring drive system in the activated position, rack  17  comprises a feeler  171  which is resting on a beak comprised in cam  16  on its largest radius, at the boundary between a snail  161  and a front edge  162 , particularly a substantially straight front edge, intended to cause the jump. 
       FIG. 6  shows the annular ring drive system in the deactivated position; feeler  171  is resting on the smallest radius of snail  161 , just after having crossed front edge  162 . 
       FIG. 8  illustrates the entire Maltese cross mechanism with an instantaneous jump function according to the invention, which combines the two sub-systems mentioned above. Planet wheels  8  are driven by arms  7  of star  4  and rotate at constant speed about plate  5 . When a planet wheel  8  reaches the six o&#39;clock position, annular ring  10  causes it to make an instantaneous half-turn on itself. As a reminder, planet wheel  8  is constantly rotated about plate  5  by star  4 , and it is angularly guided by plate  5 . 
     The sequences of the instantaneous jump of planet wheels  8  are as follows:
         approach position, as seen in  FIG. 9 : planet wheel  8  is driven by star  4 , and is guided as it slides by annular ring  10 , which is in the activated position;   pre-jump position, as seen in  FIG. 10 : planet wheel  8  is in the six o&#39;clock position of a timepiece, particularly a watch, this particular position being non-limiting; annular ring  10  guides planet wheel  8 ; annular ring  10  is still in the activated position;   jump, broken down in  FIGS. 11 to 14 , which show the permutation of recesses  821  and  822  during the half-turn manoeuvre, and in that order; planet wheel  8  is still in the six o&#39;clock position, annular ring  10  is now rotating, it moves from the activated position to the deactivated position, and, during its travel meshes with planet wheel  8  to impart a half-turn thereto; planet wheel  8  has instantaneously made a half-turn on itself; tooth  811  has moved into first recess  1801  of annular ring  10 , then second tooth  812  into second recess  1803  after first annular ring tooth  1802 , then third tooth  813  into third recess  1805  after second annular ring tooth  1804 , allowing second wheel set recess  822  to move gradually towards cylindrical shoulder  9 , i.e. the lateral sides of teeth  813  and  814  slide over shoulder  9 ;   post-jump position, as seen in  FIG. 15 : planet wheel  8  is guided by annular ring  10  and, driven by star  4 , it leaves the six o&#39;clock position and is guided by its teeth  813  and  814 , which flank its second recess  822 , on cylindrical shoulder  9  of annular ring  10 . Annular ring  10  then returns from its deactivated position to its activated position, but this movement is made more slowly than the advance of star  4 , in order not to interfere with the operation in progress with planet wheel,  8  but with the appropriate lag to be ready to make the next planet wheel, which will appear an hour later, jump instantaneously.       

     The invention offers significant advantages. It makes it possible, in particular, for a Maltese cross mechanism to make an instantaneous jump. Achieving such an instantaneous jump directly impacts the display and ensures reading reliability for the user. The indicator moves from one position to another in a clear manner, without an intermediate position; for example, the AM/PM change at twelve o&#39;clock. Thus, the user sees information that can be read clearly, precisely and unambiguously. 
     The mechanism according to the invention tolerates a backward adjustment, for example during a time-setting operation or similar, with a defect in synchronization at the instant of the jump.