Horology: time measuring systems or devices – Power supply details – Electrical
Reexamination Certificate
2000-07-19
2002-07-02
Miska, Vit (Department: 2859)
Horology: time measuring systems or devices
Power supply details
Electrical
C310S07500D, C310S156030
Reexamination Certificate
active
06414909
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an electronically controlled mechanical timepiece enabled to accurately drive time display instruments, such as hands, by using a generator to convert mechanical energy of a mechanical energy source, such as a spring, into electrical energy, and controlling the rotation cycle of the generator by operating a rotation control device by the electrical energy. The present invention also relates to a control method therefor. More particularly, the present invention relates to an electronically controlled mechanical timepiece enabled to reliably perform rate measurement, and a control method therefor.
2. Background Art
Electrical controlled mechanical timepieces described in Japanese Examined Patent Publication No. 7-119812 Official Gazette and Japanese Unexamined Patent Publication No. 8-50186 Official Gazettes are known as those each enabled to accurately drive hands fixed to a wheel train and to indicate time by using a generator to convert mechanical energy in an unwinding mode of a spring into electrical energy, and operating a rotation control device by the electrical energy to control the value of electric current flowing through a coil of the generator
Meanwhile, in the case of an ordinary quartz timepiece driven by a button-type battery and a timepiece adapted to move hands by driving a motor by using electric power generated by the generator that is driven by a oscillating weight, rate measurement is performed by feeding electric current through a coil of the motor so as to measure the accuracy of the timepiece, and by receiving leakage magnetic flux generated at that time by a rate measuring device.
However, the electronically controlled mechanical timepiece has no motor for moving hands, so that rate measurement utilizing a motor cannot be performed. Applicants of the present application, thus, considered that another coil for rate measurement was provided therein. However, in this case, such a timepiece has drawbacks in that the size thereof is large and that the cost thereof increases.
OBJECTS OF THE INVENTION
A first object of the present invention is to provide an electronically controlled mechanical timepiece, which can perform rate measurement and reduce the size thereof and decrease the cost thereof, and to provide a control method therefor.
Further, in a conventional electronically controlled mechanical timepiece, a rotation control device constituted by ICs is operated by rectifying an AC output of a generator to direct current through a rectifier circuit. In such a case, usually, a bridge rectifier circuit using 4 diodes is used as the rectifier circuit. However, in such a bridge circuit, the diodes consume considerable electric power. Thus, the conventional electronically controlled mechanical timepiece has a drawback in that such a bridge circuit is unsuitable for a rectifier circuit to be used to rectify an AC output of a generator, which can generate only a small amount of electric power and is provided in a device, such as a timepiece.
To eliminate the drawbacks, the applicants of the present application developed a rectifier circuit that was suitable for an electronically controlled mechanical timepiece and that has first and second switches, each of which is provided between a corresponding one of two output terminals of a generator and a power storage device and is controlled according to the polarity of (or voltage level at) a corresponding one of the output terminals of the generator so that when one of the switches is closed, the other switch is opened, and the boosting can be performed by intermittently closing the opened switch at short time intervals, namely, by chopping.
When both the first and second switches are closed (namely, turned on) in this rectifier circuit, the AC output terminals of the generator are short-circuited. Thus, when each of the switches is turned on, short braking is caused in the generator. Moreover, energy is stored in the coil of the generator. Further, when one of the switches is opened (namely, turned off), the generator operates, and the energy stored in the coil results in an increase in the electromotive force or voltage.
Thus, the voltage level of an output signal at each of the AC output terminals can be raised. The output voltage of the rectifier circuit can be increased for that, as compared with the case that no chopping is performed. Consequently, the charging voltage in the case of charging a capacitor can be enhanced.
However, the electronically controlled mechanical timepiece, in which such a chopping rectifier circuit is incorporated, has another drawback in that although the charging efficiency is increased, rate measurement for checking the accuracy of the timepiece is difficult to perform.
That is, in the electronically controlled mechanical timepiece, the hands are operated in synchronization with the rotation of the rotor of the generator. It is, thus, considered that the rate measurement is performed by detecting magnetic variation caused by the rotation of the rotor.
However, in the electronically controlled mechanical timepiece, which undergoes a chopping control operation, a rate measurement device detects a chopping signal, which is generated by chopping, in addition to a magnetic variation signal generated by the rotation of the rotor. This presents the additional drawback in that the accurate rate measurement is difficult to perform.
A second object of the present invention is to provide an electronically controlled mechanical timepiece, which undergoes a chopping control operation and can easily perform rate measurement, and a control method therefor.
SUMMARY OF THE INVENTION
According to the present invention, there is provided an electronically controlled mechanical timepiece having a mechanical energy source, a generator, driven by the mechanical energy source, for generating an induced electromotive force and supplying electrical energy, a power supply circuit, into which the electrical energy is charged, and a rotation control device, driven by this power supply circuit, for controlling a rotation cycle of the generator. In this timepiece, a coil of the generator is used as a rate measuring coil.
When the coil of the generator is used as the rate measuring coil, there is no need to provide an additional rate measuring coil in the electronically controlled mechanical timepiece that has no motor for driving a time display device, such as hands, in addition to the generator. Thus, as compared with the case in which the rate measuring coil is added, the size of the electronically controlled mechanical timepiece can be reduced. Moreover, the cost thereof can be decreased.
At that time, preferably, the rotation control device ceases the power generation operation of the generator, for the predetermined time, by stopping the operation of controlling the rotation of the generator at constant cycles. Moreover, during that, the rate measurement is performed by feeding electric current from the power supply circuit through the coil of the generator.
With such a configuration, when the rate is measured, actually, leakage magnetic flux, which would be caused by performing an ordinary rotation control operation of the generator, is not generated. Only leakage flux for measuring the rate is generated by feeding electric current in the coil of the generator. Thus, the signal can be reliably and easily detected by a rate measuring device. The rate-measuring accuracy can be improved.
Further, the electronically controlled mechanical timepiece may have a first switch disposed between a first input terminal of the power supply circuit and a first output terminal of the generator, a second switch disposed between the first input terminal of the power supply circuit and a second output terminal of the generator, a third switch disposed between a second input terminal of the power supply circuit and the output terminal of the generator, and a brake control circuit enabled to control the switches independent of one another.
The elec
Koike Kunio
Nakamura Hidenori
Shimizu Eisaku
Goodwin Jeanne-Marguerite
Miska Vit
Watson Mark P.
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