Horology: time measuring systems or devices – Regulating means – For setting
Reexamination Certificate
1998-06-10
2001-01-30
Roskoski, Bernard (Department: 2859)
Horology: time measuring systems or devices
Regulating means
For setting
C368S193000, C368S192000
Reexamination Certificate
active
06179464
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a disconnecting-gear device for a timepiece gear train, this gear train actuating a minute wheel from a driving member and including a plurality of wheels and pinions arranged in a chain and meshing with each other, this chain including a wheel and pinion able to be disconnected from one of the other wheel and pinions by the action of a lever controlled by a time-setting stem to interrupt the chain and stop the minute wheel.
A disconnecting-gear device answering the generic definition of the above paragraph is known. A description thereof is given, for example, in document EP-B-O 261 243 (=U.S. Pat. No. 4 862 434).
In this document, the disconnecting-gear device is also disposed between a driving element and a minute wheel. It is a wheel and pinion able to be disconnected from the minute wheel, this wheel and pinion being the wheel following the centre-wheel, known in French by the name of <<roue moyenne>>, hereinafter the <<third wheel>>, but in reality including a wheel and a pinion with a common shaft. The wheel is meshed with a second centre-pinion, whereas the pinion is meshed with the minute wheel. One of the pivots of this wheel and pinion, which will be called the third pivot, rotates in a drill hole made in a bridge, whereas the other pivot rotates in a drill hole made in a lever controlled by a time-setting stem. When the time-setting stem is pulled out, the shaft of the third wheel and pinion inclines in such a way that its pinion leaves the toothing of the minute wheel. The hour and minute display is thus stopped, the hands being then able to be set by manipulating the stem via the motion-work.
This disconnecting-gear device has the drawback of increasing the thickness of the timepiece, since it is clear that space must be provided for the third wheel in the inclined state. On the other hand, since the pinion of the third wheel meshes directly with the minute wheel, it is also clear that during a gear reconnecting the minute hand can lead to a display error, the significance of this error depending upon the position of the pinion toothing with respect to the wheel toothing at the moment of gear reconnection. If the wheel has
60
teeth, the error may be as much as plus or minus a half minute. This error may be calculated by the following formula where E is the error and n is the number of teeth of the minute wheel:
E
=
±
1
2
·
360
°
n
In the case wherein n=60, E=±3°=approximately±½ minute.
SUMMARY OF THE INVENTION
In order to overcome the drawbacks indicated hereinbefore, in addition to satisfying the preliminary description given in the first paragraph of the description, the present invention is characterised in that, when actuated, the disconnectable wheel and pinion undergoes a movement of translation with respect to the other wheels and pinions, the axes about which all the wheels and pinions rotate remaining substantially parallel to each other.
A disconnectable wheel and pinion undergoing a movement of translation with respect to the other wheels and pinions when it is actuated, is shown in document CH-A-15 953/64. This document discloses a watch including a driving element, in this case a click, transmitting the movement of an oscillator to the second wheel. The driving element and the time-setting device are arranged in such a way that when the time-setting device is brought into the active position, it causes the movement of a rocking bar carrying an intermediate wheel and pinion between a wheel actuated by the driving element and the second wheel. Moreover, in this design, the second wheel remains constantly coupled to the minute and hour hand gear train.
The design which has just been briefly described fundamentally differs from that of the present invention. It will first be noted that the rocking bar is inserted in a kinematic chain controlling the second wheel, this latter always remaining meshed with the gear train of the minute and hour hands, whereas in the present invention, the rocking bar is inserted in a kinematic chain controlling the minute wheel, the second wheel remaining permanently coupled to the driving element. It will also be noted that, in the cited document, the intermediate wheel and pinion is uncoupled from the two wheels between which it is situated, and not only, as will be seen in the present invention, from only one of the two wheels. Finally, it will be observed that interrupting a kinematic second chain, as proposed by the cited document, may lead to losing or gaining a second according to the position in which the different wheels are situated at the moment of gear reconnection. It will be seen that in the present invention, the second wheel always remains in phase with the driving element since the kinematic second chain is never interrupted.
The present invention will now be described in detail on the basis of an embodiment given by way of example and illustrated by the drawings, in which:
REFERENCES:
patent: 3972177 (1976-08-01), Vuilleumier
patent: 4262354 (1981-04-01), Sakamoto
patent: 4363554 (1982-12-01), Schaffner et al.
patent: 4555185 (1985-11-01), Vuilleumier
patent: 4862434 (1989-08-01), Hiraga et al.
patent: 8103 (1894-01-01), None
patent: 15953/64 (1966-09-01), None
ET SA Fabriques D'Ebauches
Roskoski Bernard
Sughrue Mion Zinn Macpeak & Seas, PLLC
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