Patent Publication Number: US-7596057-B2

Title: Chronograph watch with retrograde display

Description:
REFERENCE DATA 
   This application is a continuation of International Patent Application PCT/EP2005/050489 (WO2005/091086) filed on Feb. 4, 2005, claiming priority of Swiss patent application 2004CH-00239 of Feb. 17, 2004, the contents whereof are hereby incorporated. 

   FIELD OF THE INVENTION 
   The present invention concerns a chronograph watch and a movement for chronograph watch. The present invention concerns in particular a chronograph watch characterized by a new principle for displaying the counted period. 
   DESCRIPTION OF RELATED ART 
   Chronograph watches can function according to at least two different modes. One operating mode allows the current time to be displayed whilst the other mode allows the accurate duration of an event to be measured and displayed. 
   Certain electronic quartz chronographs make it possible to count durations with a resolution of a tenth or even a hundredth of second. However, in the case of a wristwatch with analog display, the space available on the dial for displaying the chronograph&#39;s indications is limited. For this reason, the displaying of the chronograph&#39;s indications, in particular of the tenths and of the hundredths, is the result of a compromise that is rarely satisfactory. 
   The usual chronograph watches often comprise three concentric hands at the centre and several small hands on sub-dials. In this text, whenever one mentions a hand at the center, one means hands placed at the center of the dial or close to this centre, and whose extremity runs the main graduation close to the dial&#39;s periphery. 
   In time display mode, the three hands at the centre indicate the current hour, minute and second respectively, whilst the hands of the sub-dials remain unused. In chronograph mode, the hours, minutes and seconds of the counted duration are generally indicated by the small hands of the sub-dials, whilst the tenths of seconds can be indicated by the central seconds hand. Other attributions of the hands in chronograph mode are also known. 
   Reading the duration counted by this type of chronograph is slow and not very intuitive. On the one hand, considerable duration variations are indicated only by minimal displacements of a small de-centered hand. On the other hand, the hour, minute and second indications are displayed by a first set of hands in time display mode and by a different set of hands in chronograph mode; the user must thus first understand which hand is assigned to which indication in each mode. The circular sub-dials have a small diameter that does not allow highly visible indexes to be placed there. It is counter-intuitive to use the small de-centered hands for displaying important durations and the larger hands at the center for fractions of this duration. Finally, the hands at the centre must be driven in chronograph mode at angular speeds much greater than those that are used during time display; flexible driving motors are thus required for driving these hands, whilst the current consumption caused by this fast displacement of large-size hands is considerable. 
   Chronograph watches with a retrograde display of the counted minutes or hours are also known. By retrograde display, we will mean in this text a display by means of a hand that can revert to its initial position only by means of an angular displacement in the opposite direction to the sense of rotation used during the measurement. Retrograde displays comprise a graduation along an open curve, for example along a segment of circle, which allows larger-size indexes to be used. However, also in this case, hour or minute indications are borne by a central hand in time display mode and by a different retrograde hand in chronograph mode. The interpretation of the displayed data is thus complex. On the other hand, the retrograde display of the counted hours restricts the maximum duration that can be counted and displayed intuitively; the hand cannot indicate a value greater than that which is at the end of the graduation. 
   Also known are chronograph watches that display the current time by means of concentric hands at the centre, and the duration counted by the chronograph by means of an additional numeric display. The numeric display increases the price of the watch and causes additional aesthetic constraints. 
   U.S. Pat. No. 5,166,912 describes a chronograph watch comprising a retrograde tenths of seconds hand at the centre. The hand points towards a graduation closed on 360°. The arrangement at the centre is not optimal; the tenths of seconds hand risks being hidden by the hour or minute hands. Furthermore, the multiplication of the hands around a same axis does not make for very intuitive reading; the user must know which hand indicates which unit. This solution is thus at most suited for displaying the counter&#39;s tenths of seconds. 
   EP1024416 describes a mechanical chronograph watch allowing fractions of seconds to be displayed by means of a retrograde hand on a small open graduation at 12 o&#39;clock. The purely mechanical construction, where the retrograde hand is returned by means of a snail that is hard to machine, restricts considerably the reading resolution that can be indicated. The described watch indicates only the fifths of seconds. 
   EP1211579 concerns a movement having small non-retrograde hands that allow, in one mode, the tenths of seconds from the chronograph to be displayed. 
   Similarly, EP1085384 describes another movement having small non-retrograde hands that also allow the tenths of seconds from the chronograph to be displayed. EP130150 describes an electronic chronograph watch allowing the hundredths of seconds to be displayed by means of a non-retrograde hand at the centre. 
   CH61025 describes a chronograph watch having a retrograde minute hand. This watch does not allow fractions of seconds to be displayed. 
   WO02/093273 concerns a chronograph watch with a retrograde display of the seconds and a window for displaying the hours and minutes in numeric form. This watch again does not allow fractions of seconds to be displayed. 
   U.S. Pat. No. 5,959,941 describes an electronic chronograph watch having a retrograde seconds hand of the chronograph. This watch again does not allow fractions of seconds to be displayed. 
   One aim of the present invention is thus to propose a chronograph watch characterized by a new principle for displaying the counted period. One aim of the present invention is in particular to improve the legibility of the chronograph&#39;s indications, in particular the tenths or even the hundredths of seconds, thus allowing the user to read and access more rapidly the sought information. Another aim is to increase the resolution of the displayed durations, this without impairing the legibility. 
   Another aim of the present invention is to limit the current consumption caused by the displacement of the hands in chronograph mode. 
   Another aim is to propose an alternative solution, preferably more intuitive, to the problem of the indication of durations counted by a chronograph. 
   BRIEF SUMMARY OF THE INVENTION 
   According to the invention, these aims are achieved, among others, by means of a chronograph watch having a first retrograde hand for indicating the tenths of seconds of the chronograph and a second retrograde hand for indicating the hundreds of seconds of the chronograph. 
   This solution has the advantage of using at least one particular additional hand for indicating the fractions of seconds of the chronograph. It is thus possible to keep the hands at the centre to display for example the hours, minutes and seconds counted by the chronograph. The display is thus more intuitive. 
   Furthermore, the fractions of seconds are indicated by retrograde hands that can be de-centered and of small size, and that can move slightly at the end of a measurement only. The electric consumption caused by displaying fractions of seconds is thus minimized. 
   Moreover, considerable duration variations are indicated by the large hands at the centre, which the user is in any cased used to read, whilst only the fractions of seconds are indicated on sub-dials. Possible errors in reading due to the lack of legibility of the small dials consequently have any influence only on the smaller fractions of the measured duration. 
   Using two distinct graduations for the tenths and the hundredths of seconds allows large-size indexes to be placed along these two graduations. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood by reading the description of an embodiment illustrated by the attached figures in which: 
       FIG. 1  illustrates by way of example a chronograph watch comprising a retrograde display according to the invention. 
       FIG. 2  is a state diagram illustrating the transitions between three possible operation modes of the inventive chronograph watch. 
       FIG. 3  illustrates diagrammatically the three axial positions of the winding push-button of the inventive chronograph watch. 
       FIG. 4  illustrates diagrammatically the two axial positions of a first push-button of the inventive chronograph watch. 
       FIG. 5  illustrates diagrammatically the two axial positions of a second push-button of the inventive chronograph watch. 
       FIG. 6  is a flux diagram showing the operation in chronograph mode of the inventive watch. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates by way of example a chronograph watch  1  according to one embodiment of the invention. The illustrated watch comprises a wristlet  12  and a case  10  including an electronic movement, not represented, for driving the hands  20  to  24  above a dial  11 . A winding push-button C and two push-buttons A, B on one flank of the case allow to control the chronograph, to set the watch and to control auxiliary functions. 
   The hands  20  to  24  include:
         A conventional hours hand  20  at the centre, driven to complete a revolution of the dial in 12 hours in time display mode and in chronograph mode.   A conventional minutes hand  22  at the centre, driven to complete a revolution of the dial in 60 minutes in time display mode and in chronograph mode.   A conventional seconds hand  21  at the centre, driven to complete a revolution of the dial in 60 seconds in time display mode and in chronograph mode.   A retrograde hand  23 , turning around an axis  230  at about 7:30 o&#39;clock and whose extremity points towards a double graduation  113  along an open circle segment.   In current-time display mode, the retrograde hand  23  indicates the tens of the date from 0 to 3; its position is thus incremented by one unit after the 9, 19 and 29 of each month. After the 28, 29, 30 or 31, depending on the number of days of the month, the hand returns to its initial position 0.   In chronograph mode, the retrograde hand  23  indicates the tenths of seconds from 0 to 9 of the duration counted by the chronograph. The extremity of the hand is oriented towards the corresponding graduation at the end of the measurement, for example at the end of counting or in intermediary time display, then returned to its initial position 0 following a resetting of the counter.   The graduation  113  is preferably regular along a segment of circle between 90 and 180°, for example a segment of circle of 162°. The hand  23  is incremented by turning anticlockwise d 1  and reinitialized in opposite direction.   A retrograde hand  24  turning around an axis  240  at about 4:30 o&#39;clock and whose extremity points towards a graduation  114  along an open circle segment. In current-time display mode, the retrograde hand  24  indicates the units of the date from 0 to 9; its position is thus incremented by one unit at midnight each day. After the 28, 29, 30 or 31, depending on the number of days of the month, the hand  24  returns to its initial position 0.   In chronograph mode, the retrograde hand  24  indicates the hundredths of seconds from 0 to 9 of the duration counted by the chronograph. The extremity of the hand is oriented towards the corresponding graduation at the end of the measurement, for example at the end of counting or in intermediary time display, then returned to its initial position 0 following a resetting of the counter.   The graduation  114  is preferably regular along a segment of circle between 90 and 180°, for example a segment of circle of 162°. For reasons of legibility, of optimal arrangement of the dial and aesthetics, the graduation  114  is preferably placed symmetrically to the graduation  113  relative to a symmetry axis 6 o&#39;clock-12 o&#39;clock. The hand  24  is thus incremented by turning clockwise d 2  and reinitialized in opposite direction       

   The watch illustrated in  FIG. 1  thus indicates that it is 10 hours, 10 minutes 0 seconds and that the date is the 25 th  if the watch is in time display mode. If the watch is in stopped chronograph mode, it indicates a duration of 10 hours 10 minutes, 0 seconds, 25 hundredths. 
   In a variant embodiment, not represented, the date is indicated in a more conventional fashion in one or several windows in time display mode as well as in chronograph mode. The hands  23  and  24  can then be used for displaying other indications in time display mode, for example power reserve, an indication measured by an additional physical sensor, etc. 
   The five hands  20  to  24  are preferably driven by five independent stepping motors. In one embodiment, the three hands at the center  20  to  22  are driven by a single stepping motor that directly drives the seconds hand  21  and, through gears, the minutes hand  22  and the hours hand  20 . 
   It will be noted that the three hands  20  to  22 , placed at the centre in concentric fashion, are driven at the same angular speed in time display mode and in chronograph mode. It is thus possible to optimize each motor driving these hands for a single speed and thus to reduce the cost of these motors, their space requirement and their consumption relatively to motors designed to function at different angular speeds. It is furthermore not necessary to use bidirectional motors for these functions. In this case, the return to 12 o&#39;clock of the three central hands will always be performed in clockwise direction. 
   The retrograde hands  23  and  24  are however driven by bidirectional stepping motors, i.e. motors capable to turn in the direct direction d 1  resp. d 2  or in the retrograde direction according to the supplied control pulses. The direct direction d 1  of the motor driving the hand  23  is anticlockwise whilst the direct direction d 2  of the motor of the hand  24  is the clockwise direction. The retrograde direction is the direction inverted to the direct direction for each of the two motors. Both motors can be optimized to reduce the consumption in the usual direct direction and to increase the speed in the retrograde direction, where a fast return to the initial position is advantageous. 
   The hands  23  and  24  return to their respective initial position by applying on the corresponding motor a number of retrograde pulses equal to the number of direct pulses used for moving them towards their current angular position, which allows consumption to be minimized. In one embodiment, the resetting of the retrograde hands  23  respectively  24  is performed by sending a number of retrograde pulses greater than the required minimum, whereas the initial position is then determined by the mechanical bankings  231  respectively  241 . 
   It will be noted that displaying the durations of the counter is particularly legible and intuitive since the hours, minutes and seconds of the chronograph are indicated by the hands allocated to these same tasks in time display mode. 
   The arrangement close to the side of the dial of the axes  230  resp.  240  of the motors driving the retrograde hands  23 ,  24  allows them to be moved away from the motors that drive the central hands and thus to better use the space available. The graduations  113 ,  114  on the segments of circle with a relatively large radius, capable of moving closer to that of the minutes graduation, allow the indexes from 1 to 9 to be spaced considerably further and thus legible indexes to be used even for displaying the tenths and hundredths of seconds. 
   It will be understood that retrograde displays can in fact be arranged at any place on the dial, for example at 9 o&#39;clock and at 3 o&#39;clock, or even on the two upper quarters of the dial, i.e. at 10:30 o&#39;clock and at 1:30 o&#39;clock, or even at noon or at 6 o&#39;clock or at the centre for example. Furthermore, several retrograde displays with radiuses and/or segments of circle or of curve of variable angular width can be used. It is also possible within the frame of the invention to use several concentric retrograde hands and/or retrograde hands at the centre. These additional displays allow for example additional data of the chronograph, for example thousandths of seconds, one or several intermediary times, a count down etc. and/or indications of the watch in modes other than the chronograph mode to be indicated. The occupation of the two lower quadrants of the dial has however the advantage of reducing the risk of one or the other of the sub-dials being partly dissimulated in chronograph mode by the hours or minutes hands in the frequent case of short duration counts. 
     FIG. 2  is a state diagram illustrating the transitions between three possible operation modes of the inventive chronograph watch  1  of the invention, comprising three control organs of which two push-buttons A and B and a winding push-button C. Initially, the watch is in state  100  to display the current time with the hands  20 ,  21 ,  22  and the two date elements with the retrograde hands  23  and  24 . By pressing during step  101  on the winding push-button C (pushed-down position C=−1), the watch switches to chronograph mode. The chronograph is first re-initialized (step  102 ) to set both retrograde hands  23  and  24  at their initial position at 0 or in another particular position. The hands at the centre  20  to  22  go to 12 o&#39;clock. Simultaneously, the state of the electronic counters (not represented) that count the measured duration is re-initialized at zero. 
   After this initialization phase  102 , the watch  1  then switches to chronograph mode during step  103 . The chronograph mode is illustrated in detail in  FIG. 6  and will be discussed further below. The watch  1  then returns in time display mode  100  when a new pressing on the winding push-button C is detected during step  104 . Other events can be used for effecting the transition  104 . 
   During step  105 , the watch switches from the time display state  100  to the hour setting state when the winding push-button C is pulled outwards in position C+1. The time displayed by the hands at the centre  20 - 22  can then be corrected by turning the winding button in one direction whilst the date displayed by the retrograde hands  23 ,  24  can be corrected by turning the winding button C in the other direction during the step  106 . Other time or date correction means, for example by means of the push-buttons A and B, can also be implemented. Furthermore, a direct switch from the chronograph mode  103  to the time setting mode  106  can also be conceived by pulling the winding button C outwards. 
   The watch then returns to the time display mode by pressing during the step  107  on the winding button to replace it in the stable intermediary position (C=0). 
   During the step  108 , the watch switches from the time display state  100  to the hand synchronization state  109  when both push-buttons A and B are pressed simultaneously during at least a predetermined period, for example during at least two seconds. This mode makes it possible to set back at 12 o&#39;clock the hours, minutes and seconds hands. In particular, it makes it possible to ensure that the hours hand points exactly at 12 o&#39;clock when the minutes hand is at noon, and that the minutes hand also points at 12 o&#39;clock when the seconds hand is at noon. During the step  109 , the hands  20 ,  21  and  22  can be displaced independently from one another by means of the push-buttons A and B for example. The watch then returns in time display mode for example by briefly pressing on the winding push-button C. 
     FIG. 3  illustrates diagrammatically the three axial positions C=−1, C=0 and C=+1 which can be taken up by the winding push-button C of the chronograph watch. The intermediary axial position C=0 is stable and is used both in time display mode as in chronograph mode; the switching from one of these to modes to the other is performed by pressing briefly on the winding push-button C until it reaches the instable pushed-down position C=−1 and returns of itself under the action of a spring towards the stable position C=0. 
   The pulled-out position C=+1 is stable and is reached by puling the winding button C outwards to switch to time setting mode. It is recalled symbolically on  FIG. 3  that in position C=+1, the winding button&#39;s rotation allows the time and date to be corrected, as indicated previously. The watch returns in time display mode respectively chronograph mode by pressing again on the winding push-button C to replace it at the intermediary position C=0. 
     FIG. 4  illustrates diagrammatically the two axial positions A=−1 and A=0 that can be taken up by the monostable push-button A. Only the external position A=0 is stable and the push-button A returns of itself to this position as soon as it is released from the pushed-down position A=−1. The push-button A allows notably to start or interrupt the counter in chronograph mode. 
     FIG. 5  illustrates diagrammatically the two axial positions B=−1 and B=0 that can be taken up by the monostable push-button B. Only the external position B=0 is stable and the push-button B returns of itself to this position as soon as it is released from the pushed-down position B=−1. The push-button B allows notably to provisionally interrupt the counter to display an intermediary time in chronograph mode. 
     FIG. 6  is a flux diagram illustrating the functioning in chronograph mode  103  of the inventive watch. The user arrives in chronograph mode from the time display mode  100  by briefly pressing on the winding push-button C, as described above in relation with  FIG. 2 . The 5 hands are in their initial position and point towards zero, and the chronograph waits during the stage  200  that the user starts a duration counting by pressing on the push-button A or that he returns in current time display mode by pressing again on the winding push-button C (transition not represented). 
   As soon as the user presses briefly on the push-button A (step  201 ), the chronograph is started and one or several electronic counters within the movement are incremented each hundredths of a second (step  202 ). The seconds hand  21 , minutes hand  22  and hours hand  20  are moved during the measurement in order to indicate the state of the counter; the retrograde hands  23  and  24  remain however unmoving. 
   When the use presses again on the push-button A (step  203 ), the counter&#39;s incrementing is interrupted. The hands at the center  20 ,  21 ,  22  are immediately immobilized whilst the retrograde hands  23  and  24  move to point towards the positions corresponding to the tenth respectively hundredth of second reached by the counter (step  210 ). The user can then read very comfortably the counted duration (total time) by means of the 5 hands  20 - 24 . 
   When, from the counting state  202 , the user presses on the push-button B (step  204 ), the hands at the center  20 ,  21 ,  22  are immediately immobilized whilst the retrograde hands  23  and  24  move to point towards the positions corresponding to the tenth respectively hundredth of second reached by the counter at the time the button was pushed (step  205 ). The incrementing of the electronic counter is however continued during this step. 
   If, from this position  205  of intermediary time display, the user presses on the push-button A (step  206 ), the chronograph is stopped. The counter&#39;s incrementing is then interrupted during the step  208  and the watch reaches again the state  210  of total time display. 
   If however the use presses again on the push-button B (step  207 ), the seconds, minutes and hours hands regain the current position reached by the counter whilst the retrograde hands return to zero (step  209 ). The chronograph then returns to the state  202  to indicate the counted duration and continue the duration counting. 
   From the state  210  (stopped chronograph indicating a total time), pressing on the push-button A (step  211 ) allows the chronograph to revert to step  201  to start the counting of a new and non-consecutive duration; the counter and the hands then indicate the total duration counted during all the preceding measuring cycles. Pressing on the push-button B (step  212 ) allows on the other hand the chronograph to be reset and all the hands to be brought back to their initial position, without however leaving the chronograph mode, i.e. returning to the step  200 . 
   The watch preferably includes a quartz movement with a 30 millimeters&#39; diameter. The indications displayed by the retrograde hands in time display mode or in other additional modes can preferably be personalized after the movements manufacturing, for example by programming, to ensure a greater versatility.