Method of harmonic tuning of at least one gong of a watch striking mechanism

Patent metadata

Field	Value
Publication number	US-12019404-B2
Application number	US-202117400760-A
Country	US
Kind code	B2
Filing date	Aug 12, 2021
Priority date	Dec 11, 2020
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

A method for tuning a gong of a striking watch. The gong is fastened at one end to a gong holder, which can be mounted in a watch case. The gong is struck by a hammer to be vibrated on a support of the measuring instrument to determine by a fast Fourier transform frequency peaks in a band of audible frequencies. A comparison in a first natural mode of a vibration frequency in the plane XY with a vibration frequency outside the plane Z is performed and a ratio calculation r=|f1p−f1h|/f1p, where f1p is the vibration frequency in the plane XY, and f1h is the vibration frequency outside the plane Z. If the ratio r is less than or equal to a desired value of 0.006, the gong is tuned. If it is greater, the method is repeated until the ratio value is achieved.

First claim

The invention claimed is:

1. A method of harmonic tuning of a gong ( 1 ) of a striking watch, the gong ( 1 ) being fastened to at least one gong holder ( 2 ) by at least one of a first end or a second end or by an intermediate portion located between the first end and the second end of the gong ( 1 ), and for which a ratio of vibration frequencies generated in a watch plane XY, and outside the watch plane along an axis Z following a strike of a hammer against the gong ( 1 ),
the method comprising:
placing the gong ( 1 ) by means of its gong holder ( 2 ) on an adapted support of a measuring instrument or placing a watch case comprising a striking mechanism with the gong ( 1 ) on an adapted support of the measuring instrument,
striking the gong ( 1 ) in a direction defined by the hammer which is external or forming part of the striking mechanism of the watch,
picking up a dynamic response of the gong activated and vibrated by the strike of the hammer, by the measuring instrument,
processing a dynamic response signal of the gong by performing a fast Fourier transform in a processor unit or in a microcontroller of the measuring instrument,
determining at least two frequency peaks which correspond, in a selected natural mode, to the vibration frequencies in the plane XY and along the axis Z of the vibrating gong in an audible frequency band from 20 Hz to 5 kHz,
calculating at least one ratio r=|fip−fih|/fip≤0.006 or r′=|fih−fip|/fih≤0.006, where fip is the vibration frequency in the plane XY of a i th selected natural mode, and fih is the vibration frequency outside the plane Z of the i th natural mode, the calculation of the ratio r or r′ depending on the direction of striking of the hammer against the gong, and
comparing the ratio r or r′ to a desired value equal to 0.006 in such a way that if r or r′ is equal to or less than the desired value of 0.006 the gong is considered tuned and if r or r′ is greater than the desired value, a gong adjustment operation is carried out before repeating the steps of the method from the striking of the gong by the hammer.

2. The method of harmonic tuning of a gong ( 1 ) according to claim 1 , wherein the dynamic response of the activated and vibrating gong is a sound or audible signal picked up by a microphone unit of the measuring instrument.

3. The method of harmonic tuning of a gong ( 1 ) according to claim 1 , wherein the dynamic response of the activated and vibrating gong is a vibratory signal picked up by a laser vibrometer.

4. The method of harmonic tuning of a gong ( 1 ) according to claim 1 , wherein all the natural frequencies of the gong in the audible frequency band from 20 Hz to 5 kHz are tuned.

5. The method of harmonic tuning of a gong ( 1 ) according to claim 1 , for which the gong ( 1 ) is configured to be disposed in a gong plane which corresponds to the watch plane, wherein the gong is struck by the hammer in one direction of the gong plane and wherein the ratio r=|fip−fih|/fip≤0.006 is calculated to determine whether gong adjustment operations must be carried out.

6. The method of harmonic tuning of a gong ( 1 ) according to claim 1 , for which the gong ( 1 ) is configured to be disposed in a gong plane which corresponds to the watch plane, wherein the gong is struck by the hammer in a direction along the axis Z, perpendicular to the watch plane or in a direction of an oblique strike, and wherein the ratio r′=|fih−fip|/fih≤0.006 is calculated to determine whether gong adjustment operations must be carried out.

7. The method of harmonic tuning of a gong ( 1 ) according to claim 1 , wherein each adjustment of the gong is carried out by milling or grinding or by local crushing of the gong material.

Assignees

• Montres Breguet Sa

Inventors

• Kadmiri Younes
• Karapatis Polychronis Nakis

Classifications

• G10K1/00

  Devices in which sound is produced by striking a resonating body, e.g. bells, chimes or gongs (multi-toned musical instruments G10D13/08; automatic carillons G10F1/10) · CPC title

• G04B21/08

  Sounding bodies; Whistles; Musical apparatus (with electro-acoustical transmitters G04C21/00, {G04B23/08; sounding arrangements in alarm clocks G04B23/028; cases with arrangements for enhancing sound production G04B37/0075; carillons and sounding boards G10F1/08, G04B1/10, G10D13/08}) · CPC title

• G04D7/00 Primary

  Measuring, counting, calibrating, testing or regulating apparatus {(measuring devices and calibers in general G01B; counters in general H03K)} · CPC title

• G04D7/002 Primary

  Electrical measuring and testing apparatus · CPC title

• G04B21/06 Primary

  Details of striking mechanisms, e.g. hammer, fan governor {(escapements in general G04B15/00; mechanisms for stabilising frequency G04B17/00; resistance regulators G05D13/00; mechanical toys A63H)} · CPC title