Hand-setting mechanism for back winding watch
United States Patent [1 1 [111 3,879,933 Ikehata 1 1 Apr. 29, 1975 [5 HAND-SETTING MECHANISM FOR BACK 3.499.280 3/1970 Erard 58/63 WINDING WATCH 3.555.919 1/1971 Odell 74/355 Primary Emminer-George H. Miller, Jr. Attorney, Agent, or Firm-Robert E. Burns; Emmanuel J. Lobato: Bruce L, Adams [57] ABSTRACT A hand-setting mechanism for a watch having a winding stem axially displaceable freely to a hand-setting position. The winding stem is used for winding the watch in its normal winding position and is displaceable axially by a crown thereon for coupling a transmission gear driven by the winding stem to a handsetting gear of a hand-setting gear train for setting the hands of a watch. Semi-automatic means in the form of a spring biasing one of the two gears to be coupled by axial movement under control of the spring is enabled when the winding stem is displaced to its handsetting position and disenabled when it is returned to its normal winding position.  
 3 Claims, 2 Drawing Figures 1 C .\\\\\\\\\\\\\\I!?. I g ll///// HAND-SETTING MECHANISM FOR BACK WINDING WATCH BACKGROUND OF THE INVENTION This invention relates generally to watches and more particularly to back winding watches and a handsetting mechanism therefore.  
  Generally in back winding watches a hand-setting operation is effected by a transmission gear mounted on the end of a hand-setting stem which meshes with a setting gear or an intermediate gear which drives the minute gear when the winding crown on the stem is pulled up. These known watches have several problems in that the transmission gear fails to mesh with the handsetting gear or intermediate setting gear when the teeth of the two gears are out of phase in respect to meshing with each other. The transmission gear is generally fixedly mounted on the winding stern and the handsetting gear or intermediate setting gear to be coupled to the transmission gear is not axially displaceable or slidable. Therefore if the gears are out of phase for meshing of the two gears when the winding stem is pulled upwardly it can only be displaced to a halfway position. Since the winding stem cannot be pulled out to its full position sometimes the wearer of the watch will attempt to forcibly pull out the winding stem from the winding position to the hand-setting position and this will result in breaking one of the two gears or the winding stem or crown thereon.  
  Another problem is that in setting the hands of the watch if the gears will not mesh when the winding stem is first pulled out the crown has to be first rotated to place the gears of the teeth of the two gears in proper phase so that the coupling can take place and then pulled outwardly. This results in the inconvenience of having to adjust the winding stem twice to adjust the gears.  
 SUMMARY OF THE INVENTION It is a principal object of the present invention to provide a novel hand-setting mechanism for a back winding watch in which the mechanism is automatically enabled by the movement of the winding stern even though the gears coupling the winding mechanism and winding step are out of phase for meshing or being coupled.  
  Another object of the present invention is to provide a hand-setting mechanism in which the winding stem is axially movable to two operative positions without restriction even if gears to be coupled thereby are out of phase for being coupled.  
  According to the present invention a watch is provided with a hand-setting mechanism comprising the winding stern of the watch which is axially displaceable from a winding first position to a hand-setting second position. The winding stem is activated by a crown for axially displacing it and rotating it. A transmission gear is rotatably driven by the winding stem and a handsetting gear train has a hand-setting gear therein coupleable to the transmission gear. Semi-automatic means enabled by the winding stem to couple the transmission gear and hand-setting gear are provided. This semi-automatic means is enabled to couple the transmission gear and the hand-setting gear even when the teeth of the transmission gear and hand-setting gear are out of phase for meshing.  
  Provision is made in the semi-automatic means of the hand-setting mechanism of the invention for mounting either the transmission gear driven by the winding stem or the hand-setting gear to be axially displaceable thereby allowing the full axial relative movement ofthe winding stem each time it is moved to the hand-setting position and in the event that there is interference between the gears. Spring means provided bias one of the two gears that are to be coupled into engagement once the gear teeth thereof are in phase for meshing or coupling.  
 BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the hand-setting mechanism for a watch according to the invention will appear from the following description of an example of the invention, and the novel features will be particularly pointed out in the appended claims and drawing in which:  
  FIG. I is a fragmentary cross section view of a watch embodying a hand-setting mechanism according to the invention; and  
  FIG. 2 is a second embodiment ofa watch embodying a hand-setting mechanism according to the invention.  
 DESCRIPTION OF PREFERRED EMBODIMENTS The drawings illustrate two embodiments of a back winding watch each provided with a hand-setting mechanism according to the invention. As illustrated in FIG. I, a rotatable winding stem I is slidable axially in opposite directions and carries a winding crown 2 at its outer end which is outside of a watch casing member 3, for example a back cover. Inside of the casing the winding stem passes axially through openings in a barrel bridge 4 and plate 5. An inner portion of the winding stem is provided with a square stem portion lb through an interconnecting intermediate step portion la.  
  A transmission gear 6 is slidably mounted for axial movement on the winding stem square portion lb that is rotatable with the winding stem when it is rotatably driven. A spring 7 disposed under the inner or lower surface of the transmission gear 6 urges the transmission gear on the stem in a direction toward the crown of the winding stern so that the transmission gear resiliently abuts on the step portion la of the winding stern. An intermediate hand-setting gear 8 of a hand-setting gear train is rotatably mounted between the plate 5 and a setting lever spring 9 so as to mesh with the transmission gear whenever the winding stem 1 is pulled out for setting the hands of the watch.  
  A hand-setting gear 10 of a hand-setting gear train meshes with the intermediate or hand-setting gear 8 and likewise meshes with a minute gear 11. The winding stem has thereon a winding gear 12 rotational on the winding stem for winding a ratchet gear wheel 13 that meshes therewith. The winding gear 12 has ratchet teeth which mesh with a clutch gear 14 which rotates with the stern when the winding crown is rotated in the winding position illustrated in the drawing. This clutch is biased toward engagement and disengages or declutches from the winding gear 12 when the winding crown 2 is pulled upwardly from its winding or first position to a hand-setting or second position. A collar on the winding stem moves it upwardly.  
  In the position illustrated in the drawing the winding crown 2 is not pulled outwardly and the winding stem from so that the teeth thereof&#39;are displaced axially&#39; downwardly from the gear teeth of the intermediate hand-setting gear 8. Therefore. it is not possible to set the hands of the watch in this state.  
  in order to set the hands the winding crown 2 is pulledoutwardly from the first position shown to a second or hand-setting position. The winding stem moves axially upwards as shown in the drawing or outwardly of the watch and at the same time the transmission gear 6 is biased axially of the stem by the spring 7. As a resultthe peripheral teeth of the transmission gear 6 are moved into engagement with the peripheral teeth of the intermediate gear 8 and both mesh smoothly with each other without hinderance once the gears are in the proper phase for meshing.  
  It will be noted that the winding stem 1 can be completely moved to its second axial position in spite of the transmission gear 6 being stopped in its axial travel at a time when it strikes against the intermediate gear 8 if the respective gear teeth of both gears are out of phase for meshing at the time since the transmission gear 6 is axially slidable on the winding stem.  
  Once the winding stem is in its hand-setting or second position the winding crown 2 can be rotated and the transmission gear 6 rotates together with the winding stem because it has an opening which is square in configuration into which the square portion lb of the winding stem fits. As the crown 2 is rotated the transmission gear 6 is properly lined-up with the intermediate gear 8 and the transmission gear is moved automatically into engagement with the hand-setting or intermediate gear 8 by the action of the spring 7 at a point where the teeth are in the proper phase for meshing. Whereby the cou pling is automatically rendered effective by the winding stem.  
 A second embodiment of a watch embodying a handsetting mechanism according to the invention as illustrated in FIG. 1. In this embodiment the parts corresponding to those of FIG. 1 have corresponding reference numerals which are primed. Thus, a winding stem 1 is mounted in a watch extending thereto through a barrel bridge 4&#39; and has a transmission gear 6&#39; fixed thereto so that this gear is unable to slide axially relative the winding stem. An intermediate hand-setting wheel 8&#39; is pivotly mounted, between the barrel bridge 4&#39; and setting lever spring 9&#39;, on an axle 15. A spring 7&#39; is disposed in a space defined between the intermediate hand-setting gear 8&#39; and the axle 15. The upper end of the spring 7 abuts on a shoulder a of the axle 15 while its lower end abuts on a washer 8&#39;c of the intermediate hand-setting gear 8 provided with a set of lower peripheral teeth 8&#39;b so that the lower surface of the intermediate hand-setting gear 8&#39; is urged to resiliently abut against stop 16 which is mounted on the axle 15. The intermediate hand-setting 8&#39; is provided with upper peripheral teeth 8a. The lower teeth 8&#39;b of the intermediate hand-setting gear 8 ordinarily mesh with the hand-setting gear 10&#39; which meshes with a minute gear 11&#39;. The stop 16 insures that the engagement position of the transmission gear with the upper teeth 8&#39;a of the intermediate hand setting gear 8&#39; takes place.  
 Consequently in this second embodiment when the wearer of the watch pulls the winding crown outwardly from its winding or first position to its second axial position for setting the watch hands, not shown, the transmission gear 6&#39; moves together with the winding stem 1&#39; and engagesor meshes with the upper teeth 8a of the intermediate hand-setting gear 8 in case that the corresponding teeth of both wheels are in phase similarly to the embodiment in FIG. I.  
 If the respective teeth of the two gears that are to be coupled are out of phase for meshing the intermediate hand-setting gear 8&#39; is lifted against the action of the spring 7 since it is slidable axially onthe axle 15. As a result the winding stem 1 can be moved freely from its first position shown in the drawing to its second or hand-setting position. By rotating the winding crown on the winding stem&#39;to set the hands the intermediate hand-settinglgear 8, which is usually biased downwardly by thespring 7&#39; moves axially to a position against the stop 16, is automatically coupled to the transmission gear whereby the hand-setting may be effected.  
  Those skilled in the art will recognize that the back winding watch provided with the hand-setting mechanism of the invention is provided with semi-automatic means for engaging the intermediate hand-setting gear with the transmission gear after the winding stem has been moved upwardly even if the teeth of the two gears are out of phase for meshing when the winding crown is pulled out to set the hands. This is accomplished since either the transmission gear or the intermediate hand-setting gear are relatively axially slidable relative to a corresponding pivot shaft and are biased for automatic coupling by means of spring which urges either one of them to engage with the other gear. Therefore the inconveniences and drawbacks of the prior art mentioned above are entirely eliminated.  
 What I claim and desire to secure by letters patent is:  
  1. In a watch, a hand-setting mechanism comprising a winding stem axially displaceable freely from a winding first position to a hand-setting second position, a crown on said winding stern for axially displacing said winding stem and for rotating it, a transmission gear rotatably driven by said winding stem, a hand-setting gear train having a hand-setting gear coupleable to the transmission gear, semi-automatic means enabled by said winding stem when displaced to said second position thereof to couple said transmission gear and said hand-setting gear when the gear teeth of said transmission gear and said hand-setting gear are in phase for meshing and for enabling said winding stem to be freely displaceable to said second position when said gear teeth are not in phase for meshing.  
  2. In &#39;a watch according to claim 1, in which said semi-automatic means comprises means on said winding stem mounting said transmission gear for axial movement relative to said winding stem and for rotation therewith, and a spring biasing the transmission gear axially toward the crown on said stem.  
  3. In a watch according to claim 1, in which said transmission gear&#39;is fixed to said winding stem for movement therewith, and in which said semi-automatic means comprises means mounting said hand-setting gear for axial movement and rotation thereon, and a spring biasing the&#39;ha&#39;nd-setting gear axially in a direction for meshing with said transmission gear.