Horology: time measuring systems or devices – Chronological – With supplemental power source
Reexamination Certificate
2002-03-01
2004-12-07
Miska, Vit W. (Department: 2841)
Horology: time measuring systems or devices
Chronological
With supplemental power source
C368S157000, C368S204000
Reexamination Certificate
active
06829199
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to electronic apparatuses, electronically controlled mechanical timepieces, methods of controlling them, programs for controlling electronic apparatuses, and storage media, and more specifically, it relates to an electronic apparatus comprising a mechanical energy source; a generator which is driven by the mechanical energy source to generate an induced voltage and output an electric energy; and a rotation controlling unit which is driven by the electric energy to control the rotation rate of the generator; an electronically controlled mechanical timepiece, methods of controlling them, a program for controlling an electronic apparatus, and a storage medium.
2. Description of the Related Art
Japanese Patent No. 7-119812 discloses an electronically controlled mechanical timepiece in which mechanical energy released from a mainspring is converted into electric energy by a generator, and a rotation controlling unit is driven by the electric energy to control a current that flows through a coil in the generator, accurately driving hands fixed to a gear train and accurately indicating time.
In this electronically controlled mechanical timepiece, the arrangement is such that a torque (mechanical energy) applied to the generator by the mainspring can rotate the hands faster than a reference speed, and the rotation controlling unit governs the rotation rate by applying a brake. More specifically, the rotation rate of the generator is governed by comparing a rotation detection signal in accordance with the rotation rate of the generator with a reference signal generated in accordance with a signal from a time reference source such as a crystal resonator and setting a brake amount for the generator (e.g., a time for which a brake is applied).
However, when the mainspring is unwound and the spring force of the mainspring is diminished, failing to provide a sufficient rotation torque for the generator, the rotation rate of the generator is diminished, and the operation of hands becomes slow, and the time indication continues becoming slower for a long time.
In this case, the operation of hands is continued although it is slow; thus, there has been a problem that when the user of the timepiece takes a glance at the timepiece to check time, the user erroneously assumes a normal operation even though the time indication is incorrect.
In order to solve the above problem, as is described in Japanese Unexamined Patent Application Publication No. 2000-28757, herein incorporated by reference, the interval at which the rotation detection signal is input is made significantly larger than the interval at which the reference signal is input (reference period). It can then be determined that the rotation rate of the generator has diminished if the value of an up/down counter to which the reference signal and the rotation detection signal are input deviates significantly from a reference value, in which case the generator is halted and the user is thereby assuredly notified of a slower time indication.
For example, a four-bit up/down counter is provided, which counts down when the reference signal is input and counts up when the rotation detection signal is input. The counter applies a brake if the counter value is larger than or equal to “8” and releases the brake if the counter value is smaller than or equal to “7”. If a large number of reference signals are input before the input of the rotation detection signal, so that the counter value becomes “2” or smaller, i.e., if the rotation rate is significantly diminished, a brake is applied to halt the generator.
However, depending on the type of electronically controlled mechanical timepiece, when the rotation rate is significantly diminished, the power generated by the generator is also sometimes diminished, failing to maintain a voltage which is capable of driving rotation controlling means constituted of ICs, etc., thereby causing the rotation controlling means to halt. When the rotation controlling means halts, brake control is not performed. Thus, even though the counter value is “2” or smaller, a brake cannot be applied to the generator, raising the possibility that the generator, and therefore the hands, cannot be halted with full assurance.
If the counter value at which the generator is halted is set to a larger value, for example, on the order of “4”, the problem that the rotation controlling means halts and a brake control cannot be performed can be avoided. However, it has been found that the counter value can temporarily drop due to a disturbance, for example, and consequently shorten the duration resulting in the generator being halted.
The technique of actively halting the generator in case where a predetermined rotation rate cannot be maintained may be required not only in electronically controlled mechanical timepieces, but also in various electronic apparatuses such as music boxes, metronomes, toys, and electric razors which include portions rotated and controlled by a mechanical energy source such as a mainspring, rubber, etc. when a precise brake control is performed to precisely control operative portions such as a drum in a music box or a pendulum in a metronome, in which case there is also a possibility that the problem described above arises.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide an electronic apparatus, an electronically controlled mechanical timepiece, methods of controlling them, a program for controlling an electronic apparatus, and a storage medium, in which the generator is assuredly halted when the rotation of the generator becomes slow, and the generator is not halted due to a temporary effect such as a disturbance, whereby the duration is extended accordingly.
SUMMARY OF THE INVENTION
An electronic apparatus in accord with the present invention includes a mechanical energy source; a generator which is driven by the mechanical energy source to generate an induced voltage and supply electric energy; and a rotation controlling unit which is driven by the electric energy to control the rotation rate of the generator; wherein the rotation controlling unit includes brake controlling means that performs a brake control for the generator by comparing a rotation detection signal indicative of the rotation rate of the generator with a reference signal generated in accordance with a signal from a time reference source; and generator halting means that applies a brake to halt the generator if the amount of braking applied to the generator by the brake controlling means in a preset time is smaller than, or equal to, a first braking preset value.
In the present invention, when mechanical energy supplied by the mechanical energy source (i.e. such as a mainspring) is high, the amount of braking applied to the generator in the preset time must be increased in order for the generator to maintain a constant rotation rate.
On the other hand, when the mechanical energy is low (such as when the mainspring being unwound), the amount of braking applied to the generator in the preset time must be decreased.
Thus, when the braking amount in the preset time becomes smaller than or equal to the first braking preset value, it is determined that the energy of the mechanical energy source itself has diminished, and the reduction is not due to a temporary disturbance. Thus, a brake is applied to the generator at that time, so that the duration is prevented from being significantly diminished by incorrectly halting the generator due to a disturbance.
Furthermore, because of the detection of a state in which the amount of braking by the brake controlling means in the rotation controlling unit is smaller than, or equal to, the first braking preset value(i.e., a state in which the brake controlling means is performing a normal brake control is detected), the situation, which has hitherto before been the case, that the rotation controlling unit is halted and a brake cannot be applied to the generator is avoided, and it can thus be assure
Koike Kunio
Nakamura Hidenori
Shimizu Eisaku
Haro Rosalio
Miska Vit W.
Seiko Epson Corporation
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