Patent Publication Number: US-6711100-B2

Title: Timepiece provided with a date having a large aperture

Description:
The present invention relates to a timepiece including hands moving above a dial and a date formed of first and second indicators on which figures are affixed indicating respectively the units and tens of said date, this date appearing through a large aperture made in the dial, said date being driven by a date crown-wheel making one revolution in thirty one days at a rate of one step per day, this crown-wheel being arranged to drive the first indicator by one step at the end of every day except at the end of the thirty-first day when it is not driven, and the second indicator at the end of the ninth, nineteenth, twenty ninth and thirty-first day of the month, said first and second indicators each being fitted with a device enabling them to keep a defined angular position when they are not being driven. 
     A timepiece with a large aperture corresponding to the generic description hereinbefore has already been proposed. This timepiece includes a date crown-wheel arranged to make one revolution in thirty-one days at the rate of one step at the end of each day. This crown-wheel includes two distinct toothings. 
     A first toothing includes thirty active teeth evenly distributed over a sector occupying the thirty thirty-first parts of the periphery of the crown-wheel so that one thirty-first part of this periphery has no teeth. This first toothing is meshed with a first star wheel carrying a disc on which the date units are affixed. It will be understood that this disc is not driven when the toothless sector of the crown-wheel is in front of the star wheel. This absence of driving is thus arranged to occur between the thirty-first of the month and the first day of the next month. Consequently, the units disc displays the FIG. 1 on two consecutive days, namely the 31 of the month which is ending and the 1 of the month which is beginning. 
     A second toothing carries four active teeth. This second toothing is meshed with a second star wheel carrying a disc on which the tens of the date are affixed. These four active teeth are arranged on the periphery of the crown-wheel so as to drive this tens disc by one step at the end of the ninth, nineteenth, twenty-ninth and thirty-first days of the month, the tens disc thus displaying respectively 1, 2, 3 and 0. 
     The units and tens discs are arranged side by side and the figures which they bear appear in a large aperture made in the dial and located on a six-o&#39;clock—midday line of the timepiece. In order to index the figures of each of the discs correctly when they are in their last position, a jumper spring is provided, acting on each of the teeth of the corresponding star wheel, these jumper springs allowing a defined angular position of the discs in question when the system is in its rest position. 
     Since the diameter of the discs is small, the pressure which the jumper springs exert on the respective star wheels must not be high to keep the discs in place, even in the event of shocks applied to the timepiece. 
     If, however, one wishes to place the date at three o&#39;clock on the timepiece or around this point (for example between one o&#39;clock and seven o&#39;clock), the construction proposed hereinbefore is not suitable and one has to use at least one indicator of large diameter having the shape of a ring covering a zone located at the periphery of the timepiece, a preferred construction lying in the use of two moving parts of large diameter located concentrically with respect to each other. 
     In this case, the simple jumper springs proposed hereinbefore, if they properly fulfil the functions expected of them in normal use, are totally insufficient if shocks are applied to the timepiece, since, in such circumstances, the indicators, because of their large size, can move forward or backwards inadvertently and even randomly so that the synchronisation which should exist between these indicators may be broken and no conventional date correction by the stem can correct it. The timepiece then has to be opened to re-establish the lost synchronisation. 
     In order to overcome this drawback, one could of course increase the pressure exerted by jumper springs on the indicators. However, such measures would have the effect of considerably increasing the torque to be provided by the motor member of the timepiece so that the working autonomy is greatly reduced. 
     The present invention has found a remedy for this drawback by proposing a system of locks acting on the mechanisms present, these locks consuming no or very little energy while locking the date indicators when they are not being driven normally by the timepiece movement. 
     To this end, the timepiece of the invention, in addition to answering the definition given hereinbefore in the first paragraph of this description, is characterised in that a first mechanism is inserted between the crown-wheel and the first indicator and that a second mechanism is inserted between the crown-wheel and the second indicator, these first and second mechanisms each being provided with means both rotating the corresponding indicator from the crown-wheel and locking said first and second indicators when they are not being driven by said crown-wheel. 
     The invention will be described in more detail now relying on the following description, which is illustrated by the annexed drawings given by way of an example of an embodiment, and in which: 
    
    
     FIG. 1 is a view showing the general appearance, according to the invention, of the calendar watch including a large aperture in which appear an indicator of the units and indicator of the tens of the date, 
     FIG. 2 shows the drive mechanism for the units indicator in a phase in which it is locked, 
     FIG. 3 shows the drive mechanism of the units indicator in a phase in which it is being driven, 
     FIG. 4 shows the drive mechanism of the tens indicator at the end of locking phase, 
     FIG. 5 shows the drive mechanism of the tens indicator in the drive phase, 
     FIG. 6 shows on the left a cross-section along the line VIa—VIa of FIG. 3, and on the right, a cross-section along the line VIb—VIb of FIG. 5, and 
     FIG. 7 shows a cross-section along the line VII—VII of FIG.  2 . 
    
    
     FIG. 1 shows a plan view of a timepiece  1  according to the invention. This timepiece includes time indicating hands  2 ,  4  and  5  which move on a dial  3  and a date  6  displaying the date of the month. The date is formed of first  9  and second  10  indicators onto which figures are affixed indicating respectively the units  11  and the tens  12  of the date, the latter appearing through a large aperture  13  made in dial  3 . 
     As is apparent in the following Figures, the date, i.e. indicators  9  and  10  which form it, is driven by a date crown-wheel  14  which completes a revolution in thirty one days at a rate of one step per day via a finger  20  activated by a movement of the timepiece, this finger being meshed on an inner toothing of the crown-wheel, this toothing being formed of thirty one teeth  19 . 
     Crown-wheel  14  is arranged to drive first indicator  9  one step per day at the end of every day except at the end of the thirtieth day when it is not driven. This same crown  14  is arranged to drive second indicator  10  at the end of the ninth, nineteenth, twenty-ninth and thirty first days of the month. The way in which the indicators are driven will be described in more detail hereinafter. As is usually the case and as FIGS. 2,  3 ,  4  and  5  show, first and second indicators  9  and  10  are each provided with a device, referenced respectively  15  and  16 , allowing them to maintain a defined angular position when they are not being driven. 
     As is usually the case and as FIGS. 2,  3 ,  4  and  5  show, first and second indicators  9  and  10  are each provided with a device, referenced respectively  15  and  16 , allowing them to maintain a defined angular position when they are not being driven. 
     This being so and as is clear in FIGS. 2 and 3, the invention is characterised in that a first mechanism  17  is inserted between crown-wheel  14  and first indicator  9 , this first mechanism being provided with means for both rotating first indicator  9  from crown-wheel  14  and for locking said indicator when it is not being driven. 
     In the same way, as is clearly shown in FIGS. 4 and 5, the invention is characterised in that a second mechanism  18  is inserted between crown-wheel  14  and second indicator  10 , this second mechanism being provided with means for both rotating second indicator  10  from crown-wheel  14  and for locking said indicator when it is not being driven. 
     A preferred embodiment example of the first and second mechanisms inserted between date crown-wheel  14  and the respective first and second indicators will now be described more precisely. It will be noted first of all (see more particularly the cross-section of FIG. 7) that a ring  21  for driving first mechanism  17  is secured to crown-wheel  14 . It can also be seen (right part of FIG. 6) that a plurality of studs  22  to  25  are secured to crown-wheel  14 , only one stud  22  being shown in FIG. 7, the other studs being visible in FIGS. 4 and 5, these studs being arranged to activate second mechanism  18 . The way in which the units and tens indicators are driven and locked will now be described in succession. 
     Driving and Locking the Units Indicator 
     Reference will be made here to FIGS. 2,  3 ,  6  and  7 . The outer edge  26  of ring  21  carried by crown-wheel  14  includes thirty particular teeth  27  which are evenly distributed over a sector occupying the thirtieth thirty-first parts of the periphery of the ring. Each tooth is preceded by a flank having a steep ramp  29  then followed by a flank having a gentle ramp  28  to form an outer cam wherein one tooth is missing (see reference  60  in FIGS.  4  and  5 ). 
     First mechanism  17  is formed of a lever  30  pivoting on a shaft  31  secured to the plate of the movement. The first end  32  of this lever is fitted with a first pin  34  which is applied, via the effect of a return spring  35  acting on the lever, against outer edge  26  of ring  21 . When ring  21  is driven in rotation, pin  34  follows the outer edge  26  of the ring like a finger sliding against a cam. Lever  30  is then animated by a back and forth movement, this movement being generated, at the end of all the days of the month, except at the end of the thirty-first day when said movement does not occur, the pin then following a tooth-free path (reference  60  referred to hereinbefore). The back and forth movement is passed on to the second end  33  of lever  30  which, via a first beak  36  with which it is provided, in turn drives a wheel  37  in rotation, this wheel being arranged to drive first indicator  9 . 
     FIGS. 2 and 3 also show that first end  32  of lever  30  is provided with a second pin  38  arranged to follow the inner edge  39  of ring  21 , this inner edge  39  also carrying thirty particular teeth  40  which are evenly distributed over a sector occupying the thirtieth and thirty-first parts of the periphery of the ring to form an inner cam which lacks a tooth cavity (see reference  61  in FIGS. 2,  3  and  4 ). The orientation of the inner cam is arranged so that its sector  61  which has no tooth cavity is located facing sector  60  which has a tooth missing on the outer cam. Moreover, first and second pins  34  and  38  and teeth  27  to  40  disposed on outer and inner edges  26  and  39  of ring  21  are arranged so that when the ring is not being driven, first pin  34  is located at the bottom of steep ramp  29  of one of teeth  41  of the outer edge of the ring, whereas second pin  38  is positioned substantially at the top of one of teeth  42  of the inner edge of the ring. This situation is shown in FIG.  2 . In these conditions, lever  30  is locked and it is impossible for it to activate wheel  37  inadvertently and, thereby, first indicator  9 , if a shock is applied to the timepiece. 
     Wheel  37  arranged between first beak  36  of lever  30  and first indicator  9  includes a star-wheel  43  profiled so as to be driven in rotation by first beak  36 . Wheel  37  also includes a pinion  44  mounted coaxial to and secured to star-wheel  43 . Pinion  44  is meshed with a crown-wheel  45  provided with an inner toothing  46 . This crown-wheel  45  carries first indicator  9  to which the FIG. 11 indicating the units of the date are affixed. 
     FIGS. 2 and 3 show finally that lever  30  is provided with a device  15  including a second beak  47  arranged to co-operate with toothing  46  of crown-wheel  45 . When first indicator  9  is not being driven, device  15  assures first a defined angular position of first indicator  9  and secondly the locking thereof. This situation is explained in FIG. 2 which shows second beak  47  inserted between two teeth  62  and  63  and toothing  46  of crown-wheel  45 . It will be understood here that device  15  has two purposes: that of indexing units indicator  9  first of all, and then that of positively locking it to prevent it from rotating inadvertently if the timepiece undergoes a shock. 
     FIG. 3 shows units indicator  9  at the start of driving. Finger  20  driven by the timepiece movement starts to drive a tooth  19  of date crown-wheel  14  which rotates with ring  21  which is associated therewith in the clockwise direction referenced by arrow A. Pin  34  of lever  30  climbs onto the steep flank of tooth  41  of ring  21  activating the lever in the direction of arrow B. First beak  36  of lever  30  has come into contact with star-wheel  43  and slides along one of its flanks to make it rotate in the anti-clockwise direction referenced by arrow E. A wing  64  of pinion  44  associated with star-wheel  43  has come into contact with a tooth  46  of crown-wheel  45  which begins to rotate in the anti-clockwise direction referenced by arrow F which drives indicator  9 , which is associated to crown-wheel  45 , in the same direction. In the meantime, second beak  47  of lever  30  has been released from teeth  62  and  63  of crown-wheel  45  allowing the units indicator to progress by one step with complete freedom. 
     It will be observed here that the gear ratio between star-wheel  43 , pinion  44  and toothing  46  of crown-wheel  45  is selected so that FIG. 11 affixed to units indicator  9  are twenty in number, namely two series of ten figures from zero to nine. 
     Driving and Locking the Tens Indicator 
     Reference will be made for this description to FIGS. 4,  5  and  6 . Date crown-wheel  14  carries four studs  22 ,  23 ,  24  and  25 , these studs also being used as means for securing ring  21  onto crown-wheel  14 . These studs are arranged and disposed angularly on crown-wheel  14  so as to drive second mechanism  18  in rotation at the end of the ninth, nineteenth, twenty-ninth and thirty-first days of the month. The second mechanism takes the form of an intermediate wheel and pinion  18  on the one hand driven by one of the four studs  22  to  25  and on the other hand arranged to mesh with second tens indicator  10 . 
     Intermediate wheel and pinion  18  includes a first wheel  48  arranged to be moved forward in rotation by studs  22  to  25  of date crown-wheel  14  and a second wheel  49  mounted coaxial to and secured to first wheel  48 . Second wheel  49  meshes with a plate  50  provided with teeth  51 . Plate  50  carries second indicator  10  to which FIG. 12 indicating the tens of the date are affixed. FIGS. 4 to  6  also show that intermediate wheel and pinion  18  includes a bolt  52  which prevents said wheel and pinion from rotating, and consequently also plate  50  which is connected thereto, when the wheel and pinion is not being driven by one of studs  22  to  25  of date crown-wheel  14 . The main object of this bolt is to block tens indicator  10  and thus to prevent if from moving inadvertently if the timepiece undergoes a shock. 
     Several bolt shapes may be envisaged for blocking the mechanism. A plate  52  with a hexagonal cut out portion has been used here, fixedly secured to the intermediate wheel and pinion and coaxial thereto. When wheel and pinion  18  is not being driven by pin  22 , FIG. 4 shows that two neighbouring tips  53  and  54  of plate  52  abut against an edge  55  of crown-wheel  14 . Conversely, when wheel and pinion  18  is being driven by pin  22 , tip  54  of plate  52  can pass into a recess  56  made in edge  55  of the crown-wheel as is illustrated in FIG.  5 . The situation illustrated by FIG. 5 shows the passage from the twenty-ninth to the thirtieth day of the month. It will be understood that there are as many recesses  56  as studs on crown-wheel  14 . The next recess  56  located facing stud  25  will allow wheel and pinion  18  to be unlocked during the passage from the thirty-first day to the first day of the next month. 
     As already mentioned in the above paragraph and as is seen in FIG. 5, finger  20  driven by the timepiece movement begins to drive a tooth  19  of date crown-wheel  14  which rotates with studs  22  to  25  which are associated therewith in the clockwise direction referenced by arrow A. Stud  22  drives first wheel  48  then second wheel  49  which is connected thereto in the direction of arrow M, this second wheel in turn driving plate  50  and indicator  10  which is associated therewith in an anti-clockwise direction referenced respectively by arrows N and P. The tens figure appear in the aperture before the change was the three (FIG.  4 ). During the change (FIG.  5 ), the tens figure appearing in the aperture is the end of the figure three and the beginning of the figure zero, if the aperture is located at three o&#39;clock. 
     It will be observed here that the gear ratio between wheel  48 , wheel  49  and plate  50  is selected so that FIG. 12 affixed to tens indicator  10  are twelve in number, namely three series of four figures from zero to three. Indicator  10  thus makes a revolution in three months. 
     It was mentioned hereinbefore that second indicator  10  is provided with a device  16  allowing it to maintain a defined angular position when it is not being driven. As FIGS. 4 and 5 show, this device is formed of a wheel  57  fixed under plate  50 , this wheel having teeth  58  on which a jumper spring  59  acts, the illustrated shape of such spring being merely an example embodiment. 
     Final Remarks 
     In addition to including an original mechanism referenced  17 ,  18  respectively, between date crown-wheel  14  and each of units and tens indicators  9  and  10 , the large date aperture which has just been described is characterised by the safety which it provides as regards its sensitivity to the various shocks that a timepiece may undergo. This lack of sensitivity is assured as a result of bolts which lock the mechanisms when they are not being driven. These bolts advantageously replace jumper springs which, as has been shown, consume a great deal of energy. The bolts described are positive means for blocking a mechanism and not resilient means, like jumper springs, which are certainly efficient at indexing an indicator with accuracy (see jumper spring  59  which indexes tens indicator  10 ) but are powerless to prevent inadvertent movements due to shocks exerted on the timepiece.