Abstract:
In a watchcase of a time-piece an internal blocking device for simultaneously blocking the push-buttons ( 10, 20 ) of the timepiece comprises an internal collar ( 11, 21 ) for each push-button pressing a gasket ( 12, 22 ) thereof against the watchcase ( 30 ) and at least one sliding element ( 40 ) providing blocking members ( 41, 42 ) for blocking the movement of the push buttons ( 10, 20 ). The sliding elements ( 40 ) are operated from outside the timepiece through the wind/set crown ( 50 ), a specific screw down button, the bezel ( 60 ) or other external members of the timepiece. The internal push buttons blocking device of the invention improves watertightness of the timepiece by a simple and reliable mechanism which is very easy and rapid to use.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention concerns an internal device for blocking push buttons of a timepiece, in particular a chronograph watch, in order to prevent un-wanted activation of said push-pieces and to improve watertightness. 
       DESCRIPTION OF THE PRIOR ART 
       [0002]    Chronograph functions of chronograph watches are usually controlled by two push buttons located at 2-o&#39;clock and 4-o&#39;clock, that is at both sides of the watch crown used to wind and set the watch. 
         [0003]    In diver&#39;s watches the push buttons must have a waterproofing system in order to prevent damages to the watch mechanism. 
         [0004]    Standard push buttons are provided with a stem which slides in an opening of the case or of a tube integral to the case and they are forced in position by elastic means. In this push buttons the waterproofing system mainly consists of a set of rubber gaskets and o-rings arranged between the head and/or the stem of the button and the opening of the case. In this case the waterproofing performances depends on the number and the efficiency of the gaskets but, anyway no waterproof features can be granted when the button is being pushed. As it is obvious, a fortuitous pressure on the push button when under water, or even the pressure of the water itself, may cause activation of the push button with serious damages to the watch mechanism. 
         [0005]    To prevent the above they are known screw-down buttons which provide a thread surface for blocking the button by means of a corresponding thread externally provided in the case, or other tube element integral to the case. When the button is screwed to the case the button is prevented from being pushed so that waterproof features are safe. The above blocking system has two main limits. First of all screw-down push buttons are complicated and big sized so that they involve relevant production costs and they have aesthetic limits that render them not suitable for classic chronograph watches. In addiction, each push button has to be independently screwed to be blocked. 
       SUMMARY OF THE INVENTION 
       [0006]    Main object of the present invention is to propose a locking device for push buttons of a timepiece, in particular a chronograph watch, able to overcome the above limits of the conventional chronograph push buttons. 
         [0007]    Further object of the present invention is to propose a locking device for push buttons of a chronograph watch apt to prevent fortuitous movement of the push buttons. 
         [0008]    Another object of the present invention is to propose a locking device for push buttons suitable to be used in any kind of chronograph watch, and with push buttons of any size and shape. 
         [0009]    The above objects are attained by an internal blocking device for push buttons of a timepiece comprising:
       at least a push button to be blocked providing an inside collar which abuts an internal surface of a watchcase;   a gasket or a o-ring interposed between said collar and said watchcase;   at least one sliding element internal to said watchcase for sliding with respect to said push-buttons to be blocked, said sliding elements providing a block member for each push button to be blocked, said block members engaging said collar of a push button thereof upon sliding movement of said sliding element;   drive means for controlling said sliding movement of said sliding element from outside said watchcase.       
 
         [0014]    Advantageously said drive means are operated through the wind/set crown of said timepiece. 
         [0015]    Preferably said wind/set crown is a screw down crown arranged so that when it is unscrewed to set the time said push buttons are unblocked and then blocked again when said wind/set crown is screwed again. 
         [0016]    When operated through the wind/set crown the drive means comprises a pinion coaxial to the wind/set crown and operated by a rotary motion of the wind/set crown, said pinion transmitting movement to a rack-like portion of the sliding elements. 
         [0017]    Advantageously the drive means comprises at least one driven gear interposed between said pinion and said rack-like portion of said sliding elements in order to reduce or improve the transmission ratio. 
         [0018]    In a preferred embodiment the drive means comprises a conical gear engaging a mating internal conical gear of said pinion, a spring member housed inside said pinion for disengaging said bevel gear from said internal conical gear, said wind/set crown being provided with a portion shaped so as to transmit rotary motion to said conical gear. 
         [0019]    Alternatively the drive means can be operated through the bezel of said timepiece. 
         [0020]    In this last case the watchcase provides at least one slot made in its upper surface for receiving a pin fastened at one end to the bezel and at its opposite end to the sliding element. 
         [0021]    Preferably, in order to have a watertight watchcase, a gasket, or two annular sealing elements are placed around said at least one slot between the bezel and the watchcase. 
         [0022]    Advantageously the bezel is provided with a screw thread coupling with a corresponding screw thread of said watchcase. 
         [0023]    Still advantageously the block members are hook-shaped members protruding from the sliding elements. 
         [0024]    In most cases the push buttons to be blocked are in number of two placed at about 2-o&#39;clock and 4-o&#39;clock of the timepiece. 
         [0025]    When the watchcase has internally a circular shape the said sliding element is advantageously an annular element. 
         [0026]    The device of the invention clearly improve watertightness of timepieces as push buttons can be used only when necessary. In addiction, when under water, the push buttons cannot be activated by the water pressure. The blocking device of the invention blocks the push buttons from inside the watchcase and it can be operated from outside by using existing watch elements, that is the wind/set crown or the bezel. These last prevents overloading the external part of the watchcase with extra elements. 
         [0027]    Furthermore the blocking device of the invention is very rapidly operated, both for blocking and for releasing the push buttons as it does not need to independently screw or unscrew each push button 
         [0028]    The push buttons do not need to be screw down buttons so that the external shape and size of the push buttons can be freely designed 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    The above and more advantages of the device of the invention will be better understood by way of preferred embodiments examples, described in the following with reference to the accompanying drawings, in which: 
           [0030]      FIG. 1  shows a portion of a perspective view of a watchcase where is mounted a blocking device according to the invention; 
           [0031]      FIG. 2  shows a front view of the blocking device of  FIG. 1 ; 
           [0032]      FIG. 3  shows a section view taken along line III-III  FIG. 1 ; 
           [0033]      FIG. 4  shows a section view of a wind/set crown taken along line IV-IV of  FIG. 1  comprising drive means of a blocking device according to the invention; 
           [0034]      FIG. 5  shows a section view taken along line V-V of  FIG. 4 ; 
           [0035]      FIG. 6  shows a view similar to  FIG. 4  where the wind/set crown and the drive means are in a different configuration; 
           [0036]      FIG. 7  shows a bottom view, in partial broken view, of a watchcase comprising a different embodiment of the blocking device of the invention; 
           [0037]      FIG. 8  shows a component of the blocking device of  FIG. 7 ; 
           [0038]      FIG. 9  shows a section view taken along the curved line IX-IX of  FIG. 7 ; 
           [0039]      FIG. 10  shows a top view of watchcase, in partial broken view, of a watchcase comprising a further embodiment of the blocking device of the invention; 
           [0040]      FIG. 11  shows an exploded view of some components of the blocking device of  FIG. 10 ; 
           [0041]      FIG. 12  shows a section view taken along the curved line XII-XII of  FIG. 10 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0042]    Referring first to  FIGS. 1 to 6  is shown a first embodiment of the invention in which a blocking device for blocking the chronograph function controlling push-buttons,  10 , is mounted in a square shaped watchcase,  30 . The push-buttons  10  and  20  are provided with an internal collar,  11 ,  21 , which is larger than the push-button housing hole of the watchcase and the collar  11 ,  21  abuts against the internal surface,  31 , of the watchcase. A gasket or o-ring,  12 ,  22 , is interposed between the collar  11 ,  21  and the internal surface  31  of the watchcase  30  and assures watertightness when the collar  11 ,  21  presses against the internal surface  31  of the watchcase  30 . A straight sliding element,  40 , is housed in a groove,  32 , made in the bottom internal surface of the watchcase  30 , and it is able to slide in it. The sliding element  40  is provided with protruding blocking members,  41 ,  42 , that, when the sliding element  40  is in its push-button blocking position, press the collars  11 ,  21  against the internal surface  31  of the watchcase  30 . The sliding element  40  is driven to slide in the groove  32  from a push-button blocking position to a push-button release position upon rotary motion of the wind/set crown  50  of the timepiece. According to a specific embodiment of the invention the wind/set crown  50 , has an end portion,  51 , shaped with an hexagonal external section which gears with a correspondent internal section of a conical gear,  52 . The conical gear  52  engages an internal conical gear of a pinion,  53 . Inside the pinion  53  is housed a spring,  54  working between a bottom internal surface of the pinion  53  and the conical gear  52 . The pinion  53  engages a driven gear,  55 , which further engages a rack-like portion,  43 , of the sliding element  40 . The wind/set stem,  56 , is connected to the crown  50  in a conventional way, and the wind/set crown  50  is connected to a housing tube,  57 , in a conventional way as well. When the wind/set crown  50  is rotated the transmission mechanism above described makes the sliding element  40  slide from the push-button blocking position to the push-button release position and vice-versa. 
         [0043]    As shown in  FIG. 6 , when the wind/set crown  50  is un-screwed or pulled out for winding or setting the time the spring  54  pushes the conical gear  52  away and it disengages from the internal conical gear of the pinion  53 . In this last configuration the rotary movement of the wind/set crown  50  is no more transmitted to the sliding element  40 . 
         [0044]    Referring to  FIGS. 7 to 9  a different embodiment of the invention applies to timepieces, i.e. wrist watches, having a substantially circular shape. In particular, the internal profile of the watchcase,  30 ′, is circular and it houses an annular sliding element,  40 ′, shown in  FIG. 8 . The external diameter of the annular sliding element  40 ′, corresponds to the internal diameter of the watchcase  30 ′, so that it slides (rotates) on the internal surfaces of the watchcase  30 ′ with its central axis coincident with a central axis of the watchcase and it does not need restraining elements such as the groove  32  of the previous embodiment. The sliding member  40 ′ has two hook shaped block members,  41 ′,  42 ′ and between them there is a rack-like portion,  43 ′, engaging the pinion  53 . The pinion  53  is rotated by rotating the crown  50  thanks to the mechanism shown in  FIGS. 4 to 6 . 
         [0045]    Referring to  FIGS. 10 to 12  a third embodiment is shown in which the blocking device is operated by rotating a bezel,  60 , of the timepiece. In a watchcase,  30 ″, are made two slots,  35 ,  36 , having a center of curvature corresponding to the center of the bezel  60 . A pin,  61 , connects the bezel  60  with a sliding element,  40 ″, passing through the slot  35 . A second pin  62  passes through the other slot  36  and can be connected to an element apt to prevent the pin  62  disengaging the slot  36 . The sliding element  40 ″ has a hole,  45 , for receiving the pin  61  and two recesses,  46 ,  47 , that define the push-button release position when they are positioned in correspondence to the collars  12 ,  22 . In this embodiment blocking members,  41 ″ and  42 ″ are defined by non recessed portions of the sliding element  40 ″. The bezel  60  is able to rotate of a little angle between two opposite end positions of the pins  61 ,  62  in the slots  35 ,  36  respectively. The rotation of the bezel  60  causes the sliding movement of the sliding element  40 ″ operated by the pin  61 . So, a first end position of the pin  61  corresponds to the push-button blocking position and the opposite end position of the pin  61  corresponds to the push-button release position. 
         [0046]    The bezel  60  could be safely fastened to the watchcase  30 ″ by providing a threaded surface in the inner portion of the bezel and a corresponding threaded surface in the upper surface of the watchcase  30 ″. Moreover, to assure watertightness of the watchcase  30 ″ gaskets or o-rings could be provided around or at sides of the slots  35 ,  36  to be pressed between the bezel  60  and watchcase  30 ″. 
         [0047]    It is clear that further embodiments of the invention could be provided and many changes or modifications could be carried out on the blocking device of the invention. 
         [0048]    The external button that operates the drive means which move the sliding element could be other than the wind/set crown  50 . The wind/set crown  50  and the push-buttons  10 ,  20  can be of any shape and size and they could be provided with more gaskets and/or o-rings arranged in a conventional way to improve watertightness. In particular the wind/set crown  50  could be a screw down crown as well as a standard crown. 
         [0049]    The drive means that operates the sliding element upon rotary motion of the crown could be simplified. For instance, the hexagonal end portion  51  of the crown  50  could be directly connected to a correspondent internal shape of the pinion  53 . 
         [0050]    Different drive means could be provided for driving the sliding element from outside the timepiece through an existing external member of the timepiece as well as through specifically intended members. 
         [0051]    The collars  11 ,  21  and as a consequence the blocking members  41 ,  42  could have a different shape. The collars must be greater in size than the aperture of the watchcase that houses the push-button and they could have whatever shape suitable to press a gasket or an o-ring against the internal surface of the watchcase. The blocking members must have a shape allowing them to abut the collar thereof when the device is in the push-button blocking position. The blocking elements could also be provided with a slope surface for making easier them to engage the collars. 
         [0052]    The sliding element has to be restrained in a way suitable to let it slide inside the watchcase with respect to the push-buttons to be blocked. The restraining means could be simply the shape of the sliding element together with the shape of the case, as shown in  FIGS. 7 to 9 , as well as specific restraining means could be provided. 
         [0053]    These and more changes and modifications could be carried out on the device of the invention still keeping safe the above disclosed advantages and remaining within the ambit of protection of the following claims. 
         [0054]    In fact, the above disclosure of specific embodiments is useful to understand the field and scope of the present invention, so that people skilled in the art is able to put it into practice by modifying and adapting the above disclosed embodiments; such modifications will be then considered as equivalent of the disclosed embodiments. The numbers and terminology used are to be intended merely for disclosure and for comprehending the scope of the invention and then they do not limit the invention.