Abstract:
For a timepiece movement, a striking train mechanism having: at least one resonant element ( 32 ) which can emit at least two sounds of different frequencies, at least two pallets ( 36 ), and at least two hammers ( 34 ) which are designed to be driven by the pallets ( 36 ) in order to strike the resonant element ( 32 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to the field of mechanical horology. It concerns, more particular, a mechanism known by one skilled in the art under the name of minute repeater. 
       BACKGROUND OF THE INVENTION 
       [0002]    A device of this type makes it possible to indicate, upon request, the time to the closest minute, using blows struck by two hammers on two different gongs. The hammers are actuated by pallets which are lifted by a striking mechanism. This mechanism comprises an hour part, quarter part and minute part, equipped with twelve, three and fourteen teeth respectively to strike the hours, quarters and minutes. 
         [0003]    In order to control the movement of these pieces, an hour snail is disposed on a star having twelve teeth, advancing by one step each hour, while a quarter snail and minute snail are adjusted on the rod of the cannon-pinion. Three levers, each provided with a sensing arm cooperating with these snails, make it possible to determine the travel of the hour, quarter and minute parts and to adjust the number of blows struck. 
         [0004]    One will find other details on this type of complication, in particular on the driving force of the repeater or on the trigger step, meaning on triggering of the striking mechanism, in the book “Théorie de l&#39;horlogerie” by Reymondin et al, Fédération des Ecoles Techniques, 1998, ISBN 2-940025-10-X, pages 219 to 224. 
         [0005]    One of the many complexities of this mechanism comes from the large number of parts which must be coordinated and adjusted so as to achieve proper operation. 
         [0006]    The present invention aims to propose a new minute repeater mechanism, implementing a relatively small number of parts, which makes it simpler to develop. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    More precisely, the invention relates to a striking part intended to be integrated into a minute repeater mechanism, comprising a rack which has, successively, along one of its edges, a toothed hour section, a tooth-free space and a toothed minute section. 
         [0008]    Advantageously, the toothed minute and hour sections of this striking part are located in different planes. 
         [0009]    Moreover, the invention relates to a timepiece comprising a minute repeater mechanism which is equipped with:
       a power source powering said mechanism,   a control member to actuate said mechanism,   a counting member to take information on the current time, including:
           an hour snail, an hour sensing arm,   a quarter snail, a quarter sensing arm,   a minute snail, a minute sensing arm,   
           a toothed hour section, one for quarters and one for minutes mounted rotatably and whereof the movement is determined by the counting member, and   means for emitting a sound comprising:
           two pallets which can be actuated by one and/or the other of the toothed sections,   two hammers moved by the pallets, and   two gongs whereon the hammers strike to emit a sound.   
               
 
         [0021]    Advantageously, the toothed hour and minute sections are located on a striking part as defined above. 
         [0022]    Another aspect of the invention relates to a striking mechanism comprising at least one resonant element which can emit at least two sounds of different frequencies, at least two pallets disposed coaxially and each comprising:
       a beak which cooperates with the toothed sections mounted mobile in said movement in order to cause said pallets to rotate,   a positioning surface whereon an elastic member bears to keep the pallets in their resting position, and   a pallet-stone which acts directly on the pin comprised by the hammers.       
 
         [0026]    The striking mechanism also comprises at least two hammers each comprising a pin whereon the pallet acts directly to cause them to strike said resonant element. 
         [0027]    Advantageously, the pallet-stone of a first pallet is positioned so as to act on the pin of a first hammer during a winding phase of its rotational movement in a first direction, and the pallet stone of a second pallet is positioned so as to act on the pin of a second hammer during a descending phase of its rotational movement in said first direction. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    Other details will appear more clearly upon reading the following description, done with regard to the appended drawing in which: 
           [0029]      FIGS. 1   a  and  1   b  are top views of the mechanism at rest, the complete view being divided between the two figures, 
           [0030]      FIGS. 2 and 3  are close ups, in top views, first, of the area of the mechanism close to the barrel and, secondly, of the pallets, gongs and hammers, and 
           [0031]      FIGS. 4 to 7  illustrate different positions of the mechanism while chiming 10:40. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    The minute repeater mechanism according to the invention is described below in reference to  FIG. 1 . It is placed in a traditional timepiece movement whereof the common elements, for purposes of clarity, are not illustrated. Likewise, the plate, whereon the parts of the repeater are assembled, does not appear in the drawing. 
       Winding and Actuation 
       [0033]    The power needed to operating the repeater is supplied by a striking barrel  10  which is wound, either by a rack which the wearer actuates, or by an oscillating weight automatic winding system, or by manual winding. 
         [0034]    In the illustrated example, the barrel  10  is automatically wound. It is kept in the wound position by a wolf tooth gear  12 . More precisely, the end of a first lever  14  visible in  FIG. 2  is mounted rotatably at the edge of the movement, forms a pawl which blocks the gear  12 . When the wearer of the watch wants to actuate the minute repeater mechanism, he presses a button  16  protruding outside the case. This actuates a second lever  18 , also located at the edge of the movement, rotating in a point X and comprising a pin  20  which cooperates with the first lever  14 , next to the center of the movement. 
         [0035]    Pressure on the button  16  causes rotation of the lever  18  whereof the pin  20  pushes the lever  14 . The pawl is then lifted, which results in freeing the barrel  10 . 
         [0036]    Through a traditional gear train, the barrel  10  causes rotation of a striking driving wheel  22 , rotating in clockwise in a point A, under the other parts of the repeater mechanism. The unwinding of the barrel is slowed by a brake  23  or an escapement disposed at the exit of the barrel  10 . 
         [0037]    The lever  18  comprises, moreover, a pin  18   c  being located, at rest, in one of two slots  200  developed on a diameter of a counting wheel  202 , named as such because, as one will understand below, it makes it possible to determine the duration of one cycle of the repeater mechanism. 
         [0038]    A gear train located at a lower lever relative to the elements already described, connects the barrel  10  to an intermediate mobile located under the counting wheel  202 , coaxially to and linked with it. It is therefore not visible in the drawing. 
         [0039]    When the button  16  is pressed, the lever  18  is lifted and the barrel  10  is freed. The counting wheel  202  is then driven in rotation and, when the button  16  is released, the pin  18   c  bears on the edge of the counting wheel  202  which has turned, which keeps the lever  18  in position and prevents the pawl from falling back and blocking the barrel  10 . When the wheel  202  has performed one half of a revolution, the pin  18   c  goes back down into the other slot  200  and the lever  18  falls back. The pin  20  of the lever  18  no longer pushes on the lever  14 , the pawl can then fall back, blocking the barrel  10 . The speed of rotation of the counting wheel  202  is adjusted to allow the striking mechanism to perform one complete cycle while this wheel performs a half-revolution. 
         [0040]    As can be better seen in  FIG. 2 , the barrel  10  is kinematically connected with a wheel  210  completing one revolution in a period substantially equal to that of the remaining power reserve of the barrel. This wheel makes it possible to display, in a window of the frame, information on the remaining running time of the striking barrel. 
         [0041]    Advantageously, the wheel  210  bears, on its axis, a cam  212  intended to cooperate with a finger  216   a  of a lever  216 . One of the ends of this lever  216  ends near the lever  18 , particularly a hook  18   a  comprised by said lever  18 . This end is provided with a pillar  216   b  located on the cam and a banking  216   c  located under it and intended to act with the hook  18   a . A jumper-spring  218  has two adjacent housings  218   a  and  218   b  which cooperate with the pillar  216   b . The interaction between the cam  212  and the finger  216   a  makes it possible to drive the pillar  216  from one to the other of the housings, the pressure of the spring  218  allowing the lever  216  to occupy only two positions. 
         [0042]    The cam  212  is positioned so as to cross the finger  216   a  when the power reserve of the barrel does not make it possible to complete a full cycle of the minute repeater striking train, meaning when it is lower than approximately 30% of the total reserve. 
         [0043]    When the remaining power reserve is greater than this value, the lever  216  is in the first of its positions, the pillar  216   b  being located in the housing  218   a  and the banking  216   c  leaving the hook  18   a  free. When the reserve becomes less than this value, the rotation of the wheel  210  and the position of the cam  212  enable this cam to push the finger  216   a  and to cause the lever  216  to move into its second position. The pillar  216   b  is then located in the housing  218   b  and the banking  216   c  is positioned in the hollow of the hook  18   a.    
         [0044]    Thus, when the wearer pushes the button  16  to trigger the minute repeater, the lever  18  cannot be actuated, as the banking  216   c  blocks it at the level of the hook  18   a . The barrel therefore cannot be freed and there is no alarm. 
         [0045]    Preferably, the display indicates in the window, when the lever is in its first position, that the repeater mechanism is usable, for example through a section of a first color and, when the lever is in its second position, that the mechanism is blocked, through a disc of another color. 
       Counting Element 
       [0046]    To take information relative to the current time, the mechanism is equipped with a counting element which comprises a set of snails of a known type, driven by the going train. In summary, it comprises a minute snail  24  equipped with four arms each provided with fourteen teeth, adjusted on a rod of the cannon-pinion at the center of the movement, and a quarter snail  26  provided with three teeth, linked with the surprise. Moreover, an hour snail  28  is disposed on a star  30  with twelve teeth, advancing by one step per hour. 
         [0047]    Advantageously and as shown in the figures, the minute snail  24  is provided with a surprise, of the traditional type, provided with a jumper-spring  31 . This mechanism aims to avoid, during passage from one quarter to the next, the minute sensing arm (described below) falling directly at the “0 minute” level. One will find explanations of this well-known device in the reference cited in the introduction. 
       Gongs and Pallets 
       [0048]    As shown particularly in  FIG. 3 , the repeater comprises, at its edge, two gongs  32   a  and  32   b  which two hammers  34   a  and  34   b , moved by upper  36   a  and lower  36   b  pallets, cause to sound. The gongs  32   a  and  32   b  can be produced in just one or several independent parts. The springs and counter-springs of the hammer are not illustrated. 
         [0049]    According to one important characteristic of the invention, these pallets are disposed coaxially. They each have:
       a beak  38  which cooperates with toothed sections in order to cause them to rotate,   one positioning surface  40  whereon bears a spring  42  to keep them in their resting position, and   a pallet stone  44  which acts directly on a pin  46  comprised by the hammers  34  to cause them to strike the gongs  32 .       
 
         [0053]    For the upper pallet  36   a , the pallet stone  44   a  is positioned so as to act on the pin  46   a  during an ascending phase of its counterclockwise rotational movement. 
         [0054]    For the lower pallet  36   b , the pallet stone  44   b  is positioned so as to act on the pin  46   b  during a descending phase of its counterclockwise rotational movement. 
         [0055]    When the toothed sections rotate counterclockwise and actuate the pallets  36  from right to left, in reference to  FIG. 2 , these are driven counterclockwise, which does not have any effect on the hammers  34  (as this distances the pallet stones from the pin  46 ), then they go back to their initial position under the effect of the spring  42 . 
         [0056]    When the toothed sections rotate clockwise and actuate the pallets  36  from left to right, in reference to  FIG. 2 , these are driven counterclockwise. The pallet stones  44  then push the pins  46 , which makes it possible to actuate the hammers  34   a  and  34   b  and to cause the gongs  32   a  and  32   b , respectively, to ring. 
         [0057]    As one will understand below, the pallets can, thanks to their structure, be actuated separately or together, according to the shape and especially the thickness of the toothed sections. Moreover, in the case where one of the toothed sections encompasses the thickness of both pallets, the relative position of the beaks makes it possible to adjust the time between the strikes of the hammers. 
       Set of Striking Parts (FIG. 1) 
       [0058]    Particularly to the invention, a striking part  100  is mounted rotatably in A. It comprises a base  100   a  having a globally triangular shape, the point A being located near one of the angles, and a rack  100   b . This rack  100   b  has successively, from left to right, along its outer edge, meaning from the outer side of the movement, a toothed hour section  106  positioned, in the direction of the thickness of the mechanism, at the level of the lower pallet  36   b , a tooth-free space  104  the role of which will appear below, and a toothed minute section  102  positioned, in the direction of the thickness of the mechanism, at the level of the upper pallet  36   a . A recess  107 , visible in  FIGS. 4 to 7  and the role of which will appear below, is developed at the level of the free space  104 . 
         [0059]    The striking part bears:
       a first spring  108  located near the toothed sections  102  and  106 , and intended to exert pressure on the free space  104 , and   a second spring  110  of the jumper type, the role of which will appear below, positioned at the level of one of the angles of the base  100   a  excluding that bearing the point A.       
 
         [0062]    Moreover, the striking part  100  bears, under it, a lever  112  visible in  FIGS. 4 to 7  and rotating in a point B. This latter part is provided with a first pin  114  intended to cooperate with the driving wheel of the striking  22 , and a second pin  116  rising up on the frame side and crossing the part  100  through an opening  118 . As one will see below, this pin  116  serves to actuate the lever. 
         [0063]    Moreover, a spring  120  is fixed, on one side on the plate and, on the other side on the striking part  100 , and exerts a force aiming to drive the part  100  counterclockwise. The banking means blocking the part  100  will be explained below. 
         [0064]    A part called a trigger  122  is mounted rotatably in A on the striking part  100  and is coupled to it by a rod  124  (or a screw, for example) which goes through an oblong hole developed in the part  100 . The trigger  122  comprises a first  128  and a second  130  arm in the shape of arcs of circle, oriented concentrically to the driving wheel  22 . The first arm  128  ends with a sensing arm  128   a  intended to cooperate with the minute snail  24 . The second arm  130  ends with a sensing arm  130   a  intended to cooperate with the hour snail  28 . 
         [0065]    Moreover, the trigger  122  has a housing  132  wherein the pin  116  of the lever  112  is positioned. Thus, thanks to the play left by the oblong opening  126 , the part  100  may move relative to the trigger  122 , which drives the rotation of the lever  112  and causes the pin  114  to engage on the driving wheel  22 . 
         [0066]    The second arm  130  is provided, on its outer edge, with a pin  134  intended to cooperate with the spring  110 . This positions the trigger  122  such that it abuts on one or the other of the ends of the oblong opening  126 . It therefore forces the lever  112  to be in one or the other of its extreme positions, meaning engaged or fully disengaged. 
         [0067]    In reference to  FIG. 6 , a quarter part  136  is mounted rotatably, by known means, in a point C located on the striking part  100 . This part  136  has, overall, the shape of a traditional striking rack. More particularly, one of its corners  136  defines, on one side, a blocking surface  136   b  and, on the other side, a support surface  136   c . This is formed by the edge of the part  136  located next to the center of the movement which draws a circle portion centered on the point A. 
         [0068]    The quarter part  136  presents, moreover, a toothed portion  136   d , arranged so as to be positioned in the free space  104 . This portion  136   d  comprises only three teeth, intended respectively to sound the first, second and third current quarter hour. Its thickness and its position allow the teeth to cross, in their travel, the beaks  130  of the two pallets  36 . In light of the structure of these pallets described above, each tooth first actuates one  36   b  then, immediately after, the other  36   a  of the pallets, thereby producing the sound typically identifying the quarters. 
         [0069]    Moreover, the quarter part  136  is provided with a pressure surface  136   e  with which the spring  108  cooperates, said spring  108  exerting a force aiming to cause the toothed portion  136   e  to wobble toward the center of the movement. Near this surface, the part  136  has a shoulder  136   g  intended to cooperate with the recess  107  of the striking part. 
         [0070]    Lastly, the part  136  comprises a boss  136   f . This boss and the toothed portion  136   d  are located on either side of the pivot point C. Thus, the boss makes it possible to actuate and rotate the part  136 . 
         [0071]    A quarter control piece  138  is assembled, under the striking part  100 , rotatable around the point A. It comprises a first arm  140  ending with a sensing arm  140   a  intended to cooperate with the quarter snail  26 . It also comprises a second arm  142  having a corner  142   a  defining, on one side, a blocking section  142   b , and, on the other side, a support section  142   c . This is formed by the edge of the arm  142  located next to the edge of the movement and draws a portion of a circle centered on the point A. The manner in which the control  138  and the quarter part  136  cooperate will be described below. 
         [0072]    As one will better understand below, a pin  144  is positioned in the plate to limit the travel of the control  138  counterclockwise. 
       Trigger Elements 
       [0073]    As one sees better in  FIGS. 4 to 7 , the second lever  18  mentioned above comprises a second hook  18   b  cooperating with a connecting rod  148  formed essentially by a first arm  148   a  and a second arm  148   b . The connecting rod is mounted rotatably on the plate at a point D located at the level of the first end of the arm  148   a . The arms  148   a  and  148   b  are hinged at a point E located at the second end of the arm  148   a  and at the first end of the arm  148   b . A spring  150  connecting the first arm  148   a  to the second end of the second arm  148   b  exerts a force keeping the arms of the connecting rod in a semi-folded position. 
         [0074]    The second end of the arm  148   b  has a first narrow cylindrical part  152  and a plate  154  having a larger diameter intended to act on the boss  136   f  of the quarter part  136  to cause it to rotate. 
         [0075]    A pin  156  is fixed in the plate. It is truncated and has a flat section  156   a  intended to cooperate with the part  152  to guide the movement of the connecting rod  148 . 
         [0076]    When the button is pressed, the lever  18 , through the hook  18   b , pushes the connecting rod close to the point D so as to cause it to rotate around this point. The cylindrical part  152  bears on the flat section  156   a , and the arms  148   a  and  148   b  unfold, putting the spring  150  under tension. At the end of the travel, the plate  154  pushes the boss  136   f , then, the part  152  exceeds the flat section. Under the effect of the spring  150 , the connecting rod  148  then goes back to its initial position, so as to avoid the plate hindering the travel of the quarter part  136 . 
       Resting Position 
       [0077]    For more clarity,  FIG. 4  provides a close up of the area proper to the repeater mechanism in the resting position. The section  142   b  and surface  136   b  for blocking the control  138  and the quarter part  136  are face to face. Indeed, the spring  108  presses the quarter part  136 , but this is positioned in abutment, thanks to the bearing of the shoulder  136   g  on the recess  107 . The section  142   b  and the surface  136   b  bear on each other under the effect of the springs  120  and  108 . Thanks to the spring  120 , all of the striking parts are positioned by bearing of the quarter control piece  138  on the pin  144  which form a banking element. 
         [0078]    The lever is not engaged on the driving wheel which does not turn, the striking barrel being kept blocked by the pawl lever  14 . 
         [0079]    The paragraphs below refer to  FIGS. 5 to 7  and explain the operation of the mechanism during the striking corresponding to the indication of 10:40. 
       Triggering 
       [0080]    To operate the striking train, the wearer presses the button  16 . On one hand, this drives, through the levers  14  and  18 , the liberation of the striking barrel  10  which causes the driving wheel  22  to rotate. On the other hand, the connecting rod  148  bears on the boss  136   f  and causes the part  136  to rotate. The blocking section  142   b  and surface  136   b , of the control  138  and the quarter part  136 , respectively, slide on one another. 
         [0081]    When, the rotation of the part  136  continuing, the corners  136   a  and  142   a  escape from one another, the assembly of striking parts formed by the part  100 , the trigger  122  and the quarter part  136 , turns counterclockwise around the point A, until the hour sensing arm  130   a  bears on the hour snail  28 . The toothed sections  102  and  136   d  actuate the pallets  36  without having any effect on the hammers. The striking part  100  positions itself such that ten teeth are upstream of the pallets, meaning that they are ready to actuate them again when the strike parts will turn clockwise, with, this time, an effect on the hammers  34 . 
         [0082]    The movement relative to the striking parts, particularly the quarter part  136 , relative to the quarter control piece  138 , brings the support surface  136   c  into contact with the support section  142   c . The spring  108  presses on the pressure surface  136   e  of the quarter part  136  which bears on the arm  142  of the quarter control piece  138 . The toothed portion  136   d  remains at the level of the toothed minute sections  102  and hour sections  106  and is able to cross the beaks  38  of the pallets  36 . 
         [0083]    The counterclockwise movement of the set of striking parts results in engaging the lever  112  on the driving wheel  22 . Thanks to the combined action of the jumper  110 , engagement only takes place after the sensing arm  130   a  has taken its information from the hour snail  28 . 
         [0084]    Once engaged, the driving wheel  22  brings all of the striking parts back clockwise. Under the effect of the pressure of the spring  108 , the friction created between the support surface  136   c  and the support section  142   c  makes it possible also to drive the quarter control piece clockwise. 
         [0085]    The ten teeth of the hour section  106  positioned upstream from the pallet  36   a  successively cross the beak  38   a  and actuate the hammer  34   a  which strikes the gong  20   a  to strike the ten hour blows. 
         [0086]    Then, still moved by the wheel  22 , the teeth of the portion  136   d  in turn cross the beaks of the pallets. Thanks to their thickness, they successively push the two pallets  36  and actuate the two hammers  34   b  and  34   a  which strike, in an out of sync manner, the gongs  32   b  and  32   a  to sound the quarters. 
         [0087]    When, still driven by the friction of the striking part, the sensing arm  142   b  of the quarter control piece  138  bears on the quarter snail  26  to take information relative to the number of quarters of the current time, the part  138  stops its movement. The corner  142   a  of the quarter control piece  138  is then positioned such that, when the corner  136   a  of the quarter part  136  arrives at the level of that  142   a  of the control, the number of teeth useful to the striking has crossed the pallets  36 . 
         [0088]    In the example illustrated in  FIG. 6  (40 minutes), when two quarters have struck, all of the striking parts continuing their movement, the corners  136   a  and  142   a  escape again. The quarter part  136  is then no longer bearing on the second arm  142  and wobbles under the effect of the spring  108  until the shoulder  136   g  bears on the recess  107 . In this way, the quarter teeth not useful to the striking (the third tooth in the example) move aside and do not cross the pallets  36  during the continuation of the movement of the striking parts. 
         [0089]    The part  100  and the quarter part  136  continue their rotation, still under the action of the driving wheel  22 . The teeth of the minute section  102  then cross the beak  38   b  of the pallet  36   b  and push it successively to actuate the hammer  34   b  which strikes the gong  20   b  to strike the minutes. 
         [0090]    The striking of minutes continues until the minute sensing arm  128   a  arrives to take its information on the minute snail  24 , which stops the movement of the trigger  122  ( FIG. 5 ). The number of teeth having then crossed the pallet  36   b  corresponds to the number of minutes to sound ( 10  in the example). The striking part  100  is still moved by the driving wheel  22 . Thanks to the oblong opening, the parts  100  and  122  then have a relative movement which actuates the lever  112  and causes the disengagement of the wheel  22 . 
         [0091]    All of the striking parts then no longer being driven, the spring  120  brings the striking and quarter parts back to the resting position described above. The counting wheel  202  makes it possible for the barrel  10  to remain freed for the duration of the cycle of the repeater mechanism. 
         [0092]    Thus a minute repeater mechanism is proposed which comprises a reduced number of parts. It is, because of this, easier to produce and adjust, particularly at the level of the quarter striking train. 
         [0093]    In one variation, the three teeth of the quarter section can actuate non-coaxial pallets, but whereof the centers of rotation are very close. It is sufficient for the distance between the two beaks to be smaller than the distance separating two consecutive teeth.