Patent Publication Number: US-7717616-B2

Title: Timepiece with an hour hand able to be moved forward or backward by one hour step

Description:
This application claims priority from European Patent Application No. 03028875.7 filed Dec. 16, 2003, the entire disclosure of which is incorporated herein by reference. 
   The present invention concerns a time zone timepiece whose hour hand can be moved forward or backward in one hour steps by means of a manually actuated time setting stem, without, however, affecting the minute display. 
   A timepiece of the aforecited type can be useful for a traveller when he passes from one time zone to another and he has to adjust his watch to the new time. Since the time difference of this new time relative to the old time, is a whole hour in one direction or another, it is useful for the person wearing the watch to have means available for instantaneously moving the position of the hour hand forward or backward by a whole hour without affecting the minute display. 
   To solve the problem raised hereinbefore, CH Patent No. 388 855 in the name of Ruch and CH Patent No. 685 965 in the name of Ulysse Nardin are already known. 
   The Ruch Patent concerns a timepiece including a local time indicating member, a time zone time indicating disc rotating about a pipe of the hour wheel, and a jumper and star-wheel device connecting said disc to the hour wheel. 
   The Ulysse Nardin Patent concerns a timepiece including an hour hand capable of being moved forward in one hour steps by means of two manually actuated push-buttons, the hand being fitted onto a pipe, first and second levers controlled by the two push-buttons acting on the teeth of a correction star-wheel fixed onto the pipe, an hour wheel fitted to pivot freely about said pipe being coupled to the correction star-wheel by a jumper mechanism, whereas an additional wheel secured to the correction star-wheel, drives a date disc. The Ulysse Nardin Patent also concerns a timepiece providing an indication of a time zone time. It does not mention the driving of an additional device such as a date mechanism. 
   The Ulysse Nardin Patent concerns a timepiece providing an indication of a time of a zone time. This patent differs however from the Ruch Patent in that the time zone indication is provided not by a disc, but by the hour hand which can be moved forward or backward in one hour steps without affecting the minute display. Moreover, the Ulysse Nardin Patent proposes driving a date mechanism. It is, however, a so-called dragging date mechanism, i.e. a mechanism which takes around two hours to pass from one indication to another. The use of a dragging date mechanism instead of an instantaneous date mechanism, i.e. a mechanism having a device allowing the date to pass instantaneously at midnight, is explained by the fact that the torque opposed by an instantaneous date mechanism when the time of the watch is set in the anticlockwise direction, is greater than the click torque between the hour wheel and the correction star-wheel, which leads to a shift of the hour hand when the calendar is driven, or even in extreme cases, to the driving of the calendar being stopped, while the hour hand moves forward less than half a step then falls back into its original position. To the Applicant&#39;s knowledge, this problem has, to date, never been solved, which is why a time zone watch of the type described hereinbefore including an instantaneous date mechanism, has never been put on the market. 
   It is an object of the present invention to overcome the aforementioned problem in addition to others by providing a time zone timepiece including an additional device opposing a resistant torque, which can be greater than the coupling torque between the hour wheel and the additional wheel. 
   The present invention therefore concerns a time zone timepiece including an hour hand capable of being moved forward or backward by one hour by means of a manually actuated time setting stem without affecting the minute display, characterised in that it further includes an instantaneous date mechanism. 
   Owing to these features, one has the possibility of quickly moving the hour hand in one hour steps without going through a usual time setting operation, which enables the minute and second display to be preserved since the watch is not stopped during correction of the time of the zone time. Moreover, the timepiece according to the invention includes an instantaneous date mechanism, which gives it a resolutely innovative appearance and gives the user increased confidence in the quality of the mechanism. 
   According to another aspect of the invention, the present invention concerns a time zone timepiece including an hour hand capable of being forward or backward in one hour steps by means of a manually actuated time setting stem without affecting the minute display, this hand being fitted onto a pipe about which an hour hand, driven by a motion work, is fitted to pivot freely, an additional wheel secured to the pipe driving an additional device, the hour hand being coupled to the additional wheel by a limited torque mechanism, the timepiece being characterised in that, outside periods in which the time of the time zone is being corrected, the hour hand and the additional wheel are also rigidly coupled by a second coupling mechanism. 
   According to a feature of the invention, the second coupling mechanism includes a pinion, which meshes simultaneously with the hour wheel and the additional wheel. 
   Usually, the only function of the torque given by the mechanism used for coupling the hour wheel and the additional wheel is to move the hour hand forward or backward by one hour steps to correct the time of the zone time or take account of the change from summer time to winter time or vice versa. The role of this torque becomes, however, a leading one when an additional device is driven by the additional wheel. Indeed, in order to assure a proper operation of the watch, this torque has to be greater than the resistant torque opposed by the additional device. In the case of watches that are currently available on the market, this condition is always fulfilled, insofar as the additional device is typically a dragging, or at best a semi-instantaneous, date mechanism. This is not the case when the additional device opposes a resistant torque greater than the torque given by the mechanism used to couple the hour wheel and the additional wheel. In this latter case, one can go as far as to observe this additional device and the hour hand stopping. This is why, in accordance with the invention, it is proposed, outside periods when the time zone is being corrected, to rigidly couple the hour wheel and the additional wheel by means of a coupling pinion. Thus, the limited torque mechanism used to couple the hour wheel and the additional wheel no longer has the function only of positioning the hour hand when the time zone is changed, which only requires a very low torque and, consequently, one that is easy to make in a small volume. In all other cases, the coupling of the hour wheel and the additional wheel is accomplished by a pinion. This arrangement proves particularly advantageous when the additional device takes the form of an instantaneous date mechanism. Indeed, such a mechanism opposes a resistant torque more than four times greater than the torque of the mechanism, which usually connects the hour wheel to the additional wheel when the time is being set in the anti-clockwise direction. 

   
     Other features and advantages of the present invention will appear more clearly from the following detailed description of an example embodiment of a timepiece according to the invention, this example being given purely by way of non-limiting illustration, in conjunction with the annexed drawing, in which: 
       FIG. 1  is a top view of a time zone mechanism; 
       FIG. 2  is a cross-sectional view along the line II-II of the time zone mechanism shown in  FIG. 1 ; 
       FIG. 3  is a top view of the time setting gear train and of the date mechanism when the time setting stem is in its rest position corresponding to normal operation and, as appropriate, to the winding position of the timepiece; 
       FIG. 4  is a cross-sectional view along the line IV-IV of the time setting gear train and of the date mechanism shown in  FIG. 3 ; 
       FIG. 5  is a top view of the time setting gear train and of the date mechanism when the time setting stem is in a first pulled-out position for correcting the time zone; 
       FIG. 6  is a cross-sectional view along the line VI-VI of the time setting gear train and of the date mechanism shown in  FIG. 5 ; and 
       FIG. 7  is a top view of the time setting gear train and of the date mechanism when the time setting stem is in a second pulled-out position for setting the time of the timepiece. 
   

   The present invention proceeds from the general inventive idea, which consists, during all of the operating phases of a time zone timepiece except those that consist in adjusting the time of the zone time, in rigidly coupling the hour wheel and the additional wheel by means of a coupling pinion. Consequently, transmission of the torque from the motion work to the additional device during the operating and time setting phases passes through the hour wheel, the coupling pinion and the additional wheel. The transmission of force between the hour wheel and the additional wheel is thus deviated via the coupling pinion, the limited torque mechanism which enables the hour wheel and the additional wheel to be coupled no longer being operated except when the time of the zone time is being set, the coupling pinion being, in this latter case, disengaged. 
   The present invention will be described in conjunction with an additional device of the instantaneous date mechanism type. It goes without saying that this example is given purely by way of illustration and that the additional device can take any other form provided that it is driven by the additional wheel. 
   It will also be understood that “setting the time of the watch” means the conventional time setting thereof, i.e. the operation that consists in moving the hour hand and the minute hand forward or backward in a concomitant manner, while “setting the time of the zone time” means the operation that consists in moving the hour hand alone forward or backward in one hour steps, the minute hand remaining still. 
     FIGS. 1 and 2  are, respectively, top and cross-sectional views of the time zone mechanism according to the invention. Designated as a whole by the general reference numeral  1 , this mechanism includes an hour wheel  2  adjusted so as to pivot freely about an hour wheel pipe  4  onto which is fitted an hour hand  6 . Hour wheel  2 , mounted on pipe  4  via a washer  8 , is driven by a motion work  10 . An additional wheel  12 , secured to hour pipe  4 , drives an additional device. In the present case, this additional device includes an instantaneous jump date mechanism designated as a whole by the general reference numeral  14 . It goes without saying that this example is given solely by way of non-limiting illustration, and that any other type of watch mechanism can form the additional device, provided that it is driven by additional wheel  12 . The choice of an instantaneous date mechanism simply allows the advantages provided by the present invention to be demonstrated, as will be described in detail hereinafter. 
   Hour wheel  2  is coupled to additional wheel  12  by a limited torque mechanism  16  which includes a spring  18  acting on teeth  20  of a correction star-wheel  22 . The correction star-wheel  22  can be integral with hour pipe  4  as shown in  FIG. 2 . According to an alternative embodiment, correction star-wheel  22  can also be formed by a separate part secured to said pipe  4 . 
   The general operating principle of time zone mechanism  1  illustrated in  FIGS. 1 and 2  is as follows. In a normal operating period of the watch, motion work  10  drives hour wheel  2  which itself drives additional wheel  12  via spring  18  and correction star-wheel  22 . 
   Indeed, the spring has two substantially vertical returning portions, which dip into two diametrically opposite corresponding elongated holes  26 , arranged in hour wheel  2 , said spring  18  being secured in rotation by said returning portions to said hour wheel  2 . Thus, when hour wheel  2  rotates, it drives spring  18 , which in turn drives correction star-wheel  22 . Since the latter is secured to hour wheel  4 , hour hand  6  moves forward and additional wheel  12  rotates, driving date mechanism  14 . Conversely, when one wishes to change time zone, one rotates a time setting stem  28  (see  FIG. 3  and following) which drives the additional wheel via a correction gear train  30 . During the time that it takes to change the time zone, hour wheel  2  can be considered as being practically immobile. Consequently, additional wheel  10 , and thus hour pipe  4  and correction star-wheel  22  rotate, whereas spring  18 , immobilised in rotation by hour wheel  2 , is compressed and jumps from a space between two teeth  20  of correction star-wheel  22  to the space immediately after. The work of spring  18  in compression and then let down is made possible by the fact that its returning portions  24  are free to move radially in elongated holes  26  of additional wheel  12  in which they are received. Thus, hour hand  6  can move forward or backward in one hour steps without the minute display being altered, although the watch continues to work. It will be noted that for the coupling of the two wheels to be possible, hour wheel  2  and additional wheel  12  must also have the same number of teeth and the same module. Furthermore, the teeth of the two wheels  2  and  12  have to be superposed when they are assembled and the number thereof must be a multiple of twelve. 
   As already explained hereinbefore, the main interest of the invention lies in the fact that it provides a timepiece including a mechanism for changing the time of a time zone to which an additional device can be added, such as an instantaneous date mechanism, which opposes a resistant torque that can be up to four times higher than the torque produced by the mechanism used to couple the hour wheel to the additional wheel. Such a timepiece will be described with reference to  FIG. 3  and following, annexed to the present patent application. 
     FIGS. 3 and 4  are views, respectively top and cross-sectional views, of the time setting gear train  32  and of the date mechanism  14  when the time setting stem  28  is in its rest position corresponding to normal working, and, where appropriate, to the winding position of the timepiece when the latter is driven by a barrel spring (not shown). In this position of time setting stem  28 , motion work  10  is driven by the cannon-pinion (not shown). Motion work  10  includes a motion work wheel  36  and a motion work pinion  38 , which only drives hour wheel  2 . In turn, hour wheel  2  drives additional wheel  12 , without, however, coupling mechanism  16 , which includes correction star-wheel  22  and spring  18 , being solicited. In fact, hour wheel  2  and additional wheel  12  are rigidly coupled by a coupling pinion  40 , which transmits the movement of said hour wheel  2  to said additional wheel  12 . Finally, the additional wheel meshes with an intermediate wheel set  42 , which itself drives date mechanism  14 . 
   As can be seen upon examining  FIGS. 3 and 4 , coupling pinion  40  is carried by a rod assembly  44 . More specifically, this rod assembly  44  includes a coupling lever  46  which carries coupling pinion  40  and whose position is controlled by a control lever  48 , which is itself controlled by a pull-out piece  50  connected to time setting stem  28 . It can also be seen that control lever  48  carries two sliding pinions, namely a time setting sliding pinion  52  and an additional sliding pinion  54 . Depending upon the position occupied by control lever  48 , time setting sliding pinion  52  and additional sliding pinion  54  mesh respectively with motion work wheel  36  or with an additional intermediate wheel  56  which itself drives additional wheel  12 . Finally, the rotational movements imparted by the user of the watch to time setting stem  28  are communicated to sliding pinions  52  and  54  via a corrector intermediate wheel  58  with which said two sliding pinions mesh. Coupling lever  46  is pivoted on the arbour of additional intermediate wheel  56 , whereas control lever  48  is pivoted on the arbour of corrector intermediate wheel  58 . 
     FIGS. 5 and 6  are respectively top and cross-sectional views of time setting gear train  32  and date mechanism  14  when time setting stem  28  is in a first pulled out position for correcting the time zone time. In this first pulled out position of time setting stem  28 , pull out piece  50  pivots and in turn causes control lever  48  and coupling lever  46  to pivot so as to move coupling pinion  40  away so that it is no longer meshed with hour wheel  2  and additional wheel  12 . At the same time, additional sliding pinion  54  meshes with additional intermediate wheel  56 , which is itself meshed with additional wheel  12 . In this position of time setting stem  28 , time zone mechanism  1  plays its conventional part. In fact, when the user rotates said time setting stem  28 , this causes the simultaneous rotation of corrector intermediate wheel  58 , of additional sliding pinion  54 , additional intermediate wheel  56  and finally, additional wheel  12 . While rotating, additional wheel  12  drives correction star-wheel  22 . During the time that it takes to change the time zone, hour wheel  2  can be considered as being practically immobile. Consequently, spring  18  is immobilised in rotation by said hour wheel  2 , and will be compressed and jump from a space between two teeth  20  of correction star-wheel  22  to the space immediately after. Thus, hour hand  6  can move forward or backward in one hour steps without the minute display being altered, although the watch continues to work. 
     FIG. 7  is a top view of time setting gear train  32  and of date mechanism  14  when time setting stem  28  is in a second pulled out position for setting the time of the watch, a position in which time setting sliding pinion  52  meshes with motion work  10 , which itself drives hour wheel  2  coupled to additional wheel  12  by coupling pinion  40 . 
   When the time of the watch is being adjusted in the clockwise direction, it does not raise any particular problems. The user rotates time setting stem  28  whose rotational movement is transmitted to time setting sliding pinion  52  via corrector intermediate wheel  58 . Time setting sliding pinion  52  then meshes with motion work  10  whose pinion  38  drives hour wheel  2 . In turn, hour wheel  2  drives additional wheel  12  via coupling pinion  40  via which these two wheels  2  and  12  are rigidly coupled. Finally, additional wheel  12  meshes with intermediate wheel set  42 , which itself drives date mechanism  14 . As can be observed, when the time of the watch is adjusted in the clockwise direction, the situation is identical to the normal operation mode of the watch. 
   The difficulties arise when the time of the watch is adjusted in the anti-clockwise direction. In fact, in this case, the date mechanism can oppose a resistant torque which can be up to four times higher than the torque of mechanism  16  to spring  18 , via which hour wheel  2  and additional wheel  12  are coupled. In such case, coupling pinion  40  via which said hour wheel  2  and additional wheel  12  are rigidly coupled, plays its part fully. In fact, in the absence of this coupling pinion  40 , it would be quite impossible to set the time of the watch anti-clockwise. This is due to the fact that date mechanism  14  is an instantaneous jump mechanism, including, in particular, a cam  60  whose profile has a steep slope  62  at one location on its length. More specifically, instantaneous jump date mechanism  14  includes a date wheel  64  driven by intermediate wheel set  42  and which in turn drives cam  60  via a pin  66 . Pin  66  is housed in a slot  68  arranged in date wheel  64  inside which said pin  66  is capable of moving. Date mechanism  14  also includes a mobile finger  70  that is free to rotate with respect to date wheel  64  but is connected in rotation to cam  60  via pin  66 . Finally date mechanism  14  includes a trigger lever  72  whose beak  74  is kept applied against the profile of cam  60  by a spring  76 . 
   An instantaneous date mechanism is, let us recall, a mechanism allowing the date to change instantaneously at midnight. The time for winding the elements of the mechanism is several hours, typically of the order of eighteen hours, the energy being abruptly returned at midnight. In the present case, energy is provided by trigger lever  72 , which, following the profile of cam  60 , moves away from its rest position and enables spring  76  to store energy. During the date mechanism winding phase, beak  74  of trigger lever  72  first of all encounters a gentle slope  78 , then a contour  80 , before abruptly falling at steep slope  62 . When lever  72  falls, it causes finger  70  and cam  60  to pivot, finger  70  driving a date ring  82  through one step. At the same time, pin  66  moves into slot  68  and the system remains in that state until date wheel  64  has caught up with said pin  66 . 
   Thus, it is clear that if the time of the watch is set in the anti-clockwise direction, it can happen that beak  74  of trigger lever  72  is forced to climb up steep slope  62  of cam  60 . The date mechanism then opposes such a high resistant torque that, in the absence of coupling pinion  40 , time zone mechanism  1  could not operate and would stop the calendar being driven, while the hour hand would move forward less than one step and fall back into its initial position. The presence of coupling pinion  40 , which temporarily couples hour wheel  2  and additional wheel  12  rigidly, enables this problem to be solved by providing a higher coupling torque than the resistant torque opposed by the date mechanism. 
   It goes without saying that the present invention is not limited to the embodiment that has just been described and that those skilled in the art can envisage various simple alterations and variants without departing from the scope of the present invention.