United States Patent
US Patent 4068461: Digital electronic alarm watch
US 4068461 ยท granted 1978-01-17
| Patent Number | 4068461 |
|---|---|
| Title | Digital electronic alarm watch |
| Filed | 1976-04-15 |
| Granted | 1978-01-17 |
| Inventor(s) | John R. Fassett, Ivan V. Rondas, Joseph P. George, Claus Sondermann |
| Assignee | Frontier Co Ltd |
| CPC Classification | G04G13/021, G04G13/02, H05K3/30 |
| Number of Claims | 4 |
Abstract
A digital electronic wristwatch is provided with an alarm which includes a piezoelectric crystal mounted to vibrate a watch element. The piezoelectric crystal is supplied with a pair of signals, each having a peak voltage equal to that of the battery, but one of these signals is inverted, resulting in a peak-to-peak voltage which is higher than that normally available from the batteries located within the wristwatch housing. Such driving substantially increases the sound output of the crystal due to the effective voltage increase. A unique spring contact arrangement is used to connect the piezoelectric crystal to the watch electronics, and to permit easy removal of the piezoelectric crystal for battery replacement or watch repair. In addition, a flexible mounting arrangement increases the sound output from the alarm while providing water and dust protection for the watch.
Claims Summary
1. A method of driving a piezoelectric, audible tone producing crystal of a wristwatch, comprising:producing an audio frequency signal, said producing step comprising:generating in a crystal controlled oscillator the fundamental time base signal for said wristwatch;