US3603076A - Timepiece comprising an optical means for indicating the beat of the seconds - Google Patents

Abstract

An optical means for indicating the beat of the seconds of a timepiece includes an obturator mounted under the window in the dial of the timepiece. The obturator is mounted on a shaft having a pinion gear engaging a gear wheel on the escapewheel of the timepiece.

Description

United States Patent 1 I 1 l l lnventor Xavier Theurlllal La Chaux dc Fonds, Switzerland Appl. No. 41,003

Filed May 27, 1970 Patented Sept. 7, 1971 Assignee Mondia SA.

La Chaux de Fonds, Canton of Neuehatel, Switzerland TIMEPIECE COMPRISING AN OPTICAL MEANS FOR INDICA'IING THE BEAT OF THE SECONDS 5 Claims, 2 Drawing Figs.

US. Cl u 58/127 R lnt.Cl A v..G04b19/06 Field olSearch 514/152 R, 1521 1520, 152H, l2fiR. 127A,126B. 125B,

[56] References Cited UNITED STATES PATENTS 2,297,838 10/1942 Menkin 58/152 FX 2,891,378 6/1959 Ducommun 58/127 R FOREIGN PATENTS 757,036 9/1956 Great Britain 58/ l 52 F 177,973 9/1935 Switzerland 58/152 F 316,845 12/1956 Switzerland 58/152 F 332,545 10/1958 Switzerland 58/152 F Primary Examiner-Riehard B. Wilkinson Assistant ExaminerStanley A. Wal Attameys- Kenwood Ross and Chester E. Flavin ABSTRACT: An optical means for indicating the beat of the seconds of a timepiece includes an obturutnr mounted under the window in the dial of the timepiece. The nbturutor is mounted on a shaft having a pinion gear engaging a gear wheel on the eseapewheel of the timepiece.

PATENTEU SEP 7 m1 INVENTOR. Xavier- THEUR/LLAT BY finwvd 3 TIMEPIECE COMPRISING AN OPTICAL MEANS FOR INDICATING THE BEAT OF THE SECONDS The present invention relates to a timepiece comprising an optical means for indicating the beat of the seconds comprising an obturator moving under a window provided in the dial so that at each second the appearance of the bottom of the window changes rapidly.

Such timepieces are known per se. In the prior executions, the obturator of the window was constituted by a flat element comprising three sectors directly secured on the shaft of the escape-wheel of the conventional lever escapement mechanisms, operating at 18,000 vibrations per hour.

This arrangement shows some drawbacks which, practically, prevent its commercial use: Especially, the position normally occupied by the escape-wheel in the movement does not permit to locate the window or windows of the dial to suitable places. The dimension of these windows, limited to a sector of i2", is too narrow, that renders difi'icult the observation. Moreover, the important increase of the inertia moment of the escape-wheel, due to the presence, on its shaft, of the obturator, which is of relatively great diameter, is an aberration from the point of view of the watchmaking.

The object of the present invention is to provide a timepiece as hereabove mentioned which, however, does not present these drawbacks.

The timepiece according to the invention is characterized by the fact that the obturator is rigid with a pinion meshing with a gear wheel rigid with the shaft of the escape-wheel.

The drawing shows, by way of example, two embodiments of the invention.

FIGS. l and 2 are plan views of a portion of two wristwatches provided with an indicator indicating the beat of the seconds, in which only the elements necessary to the understanding of the invention have been represented.

Each of the watches represented comprises a lever escapement mechanism comprising an escape-wheel 1 and a lever 2. In these two embodiments, the shaft of the escape-wheel, designated by 3, carries a gear wheel 4, diagrammatically represented in the drawing, rotating in the direction of the arrow 5 and which meshes with a pinion 6 also represented diagrammatically.

In the embodiment of FIG. 1, the shaft 7 of the pinion 6 carries a disc 8 having the shape of a sector of circle extending on l80, moving under a circular window 9 provided in the dial of the watch, which has not been represented. The color of the upper face of the sector 8 is different from this of the bottom of the window 9 constituted by the portion of the base plate of the movement which is visible through this window when the sector 8 is not located thereunder.

The escapement mechanism operating at 18,000 vibrations/hour, the escape-whee], and consequently the driving gear wheel 4, rotate at the speed of one revolution per six seconds. The ratio of demultiplication between the pinion 6 and the gear wheel 4 being of 1:3, the pinion 6, and consequently the obturator 8, rotate at a speed of one revolution per two seconds. Consequently, the obturator, the sector of which extends on 180", uses one second for passing under the window 9 and, once its trailing edge has passed over the center of the window, a new second is necessary before its leading edge arrives at this same point.

The appearance of the bottom of the window thus changes each second.

In the embodiment of FIG. 2, the shaft 7 of the pinion 6 carries an obturator constituted by a disc 10 provided with two diametrically opposed sectors 10a passing under a window ll, having the shape of a segment of crown, provided in the dial, which has not been represented. The disc 10 rotating at a speed of one revolution per two seconds, as the sector 8 of the first embodiment, the sectors 10a pass under the window 11 at the rate of one per second. Their width being relatively small and corresponding to this one of the window, which extends on 36, the duration of their passage under the window is relatively short and the beat of the seconds appears like a rapid flash due to the difference of appearance (color) between the disc 10 and the bottom of the window ll.

The present invention has the advantage, due to the multiplication between the gear wheel rigid with the escape-wheel and the pinion rigid with the obturator, to increase the speed of the displacement of the obturator and consequently its travel per each second, that permits to increase the dimension of the window.

Due to the fact that the obturator is light and rotates in nonlubricated bearings, and has no force to transmit since it is connected in derivation on the gearing of the movement, it operates like a regulating flywheel; the experience has shown that the same watch has a running precision different according it is or not provided with the obturator, the presence of the obturator producing an improvement in this running preci- SlOn.

By a suitable choice of the gearing ratio between the gear wheel rigid with the escape-wheel and the pinion rigid with the obturator, the present arrangement can be applied to watches operating at any rate of vibrations which is a multiple of 3,600. For instance, for a frequency of 36,000 vibrations/hour, and with an escapement mechanism the escapewheel of which has 21 teeth, the gear wheel rigid with the escape-wheel will have 42 teeth and the pinion rigid with the obturator 10 teeth. This way, this pinion rotates at a speed of l revolution per second, and the obturator is of the type of this one of the embodiment of FIG. 2, but with only one sector extending on 36'.

What I claim is:

l. A timepiece comprising a dial having a window therein; a first and second shaft rotatably mounted in parallelism in said timepiece; an escape-wheel and a gear wheel rigidly mounted on said shaft; and an obturator and a pinion gear rigidly mounted on said second shaft, said obturator being located beneath and in close proximity to said window, said gear wheel being in driving engagement with said pinion gear whereby the rapid change in the appearance of said window due to the movement of said obturator indicates the beat of the seconds.

2. A timepiece as claimed in claim 1 wherein said obturator consists of a disc means the configuration of which is an arcuate sector.

3. A timepiece as claimed in claim 2 wherein said sector extends I".

4. A timepiece as claimed in claim 2 wherein said obturator is provided with two arcuate sectors having a predetermined width, said two sectors being diametrically opposed.

5. A timepiece as claimed in claim 4 wherein each of said two arcuate sectors extends 36.

Claims (5)

1. A timepiece comprising a dial having a window therein; a first and second shaft rotatably mounted in parallelism in said timepiece; an escape-wheel and a gear wheel rigidly mounted on said shaft; and an obturator and a pinion gear rigidly mounted on said second shaft, said obturator being located beneath and in close proximity to said window, said gear wheel being in driving engagement with said pinion gear whereby the rapid change in the appearance of said window due to the movement of said obturator indicates the beat of the seconds.

2. A timepiece as claimed in claim 1 wherein said obturator consists of a disc means the configuration of which is an arcuate sector.

3. A timepiece as claimed in claim 2 wherein said sector extends 180*.

4. A timepiece as claimed in claim 2 wherein said obturator is provided with two arcuate sectors having a predetermined width, said two sectors being diametrically opposed.

5. A timepiece as claimed in claim 4 wherein each of said two arcuate sectors extends 36*.

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