US3648453A - Electric timepiece - Google Patents

Electric timepiece Download PDF

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Publication number
US3648453A
US3648453A US842278A US3648453DA US3648453A US 3648453 A US3648453 A US 3648453A US 842278 A US842278 A US 842278A US 3648453D A US3648453D A US 3648453DA US 3648453 A US3648453 A US 3648453A
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United States
Prior art keywords
frequency
vibrator
mechanical vibrator
time standard
mechanical
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Expired - Lifetime
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US842278A
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English (en)
Inventor
Susumu Aizawa
Koichi Nakamura
Yuki Tsuruishi
Kikuo Oguchi
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Suwa Seikosha KK
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Suwa Seikosha KK
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    • GPHYSICS
    • G04HOROLOGY
    • G04CELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C3/00Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means
    • G04C3/04Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance
    • G04C3/06Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance using electromagnetic coupling between electric power source and balance
    • G04C3/065Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance using electromagnetic coupling between electric power source and balance the balance controlling gear-train by means of static switches, e.g. transistor circuits
    • G04C3/067Driving circuits with distinct detecting and driving coils
    • GPHYSICS
    • G04HOROLOGY
    • G04CELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C11/00Synchronisation of independently-driven clocks
    • G04C11/08Synchronisation of independently-driven clocks using an electro-magnet or-motor for oscillation correction
    • G04C11/081Synchronisation of independently-driven clocks using an electro-magnet or-motor for oscillation correction using an electro-magnet

Definitions

  • the present invention relates to an electric timepiece, and more particularly to an electric timepiece comprising a timekeeping oscillator and a mechanical vibrator which drives the gear train to operate the indicators.
  • a primary object of the present invention is to provide a high-precision electric watch which is simple in construction and cheap in price, by synchronizing the mechanical vibrator of unstable low frequency with the time-keeping oscillator of high frequency, without using a frequency divider.
  • a further object of the invention is to provide a high-precision wristwatch controlled by a quartz crystal.
  • a watch using, as its time base, a tuning fork which vibrates at several hundred cycles is also known.
  • the gear train is driven directly by the tuning fork.
  • the daily rates of these watches are nearly 2 seconds, it is still impossible to attain a precision of 0.2 second per day or better. This is because the fluctuation of the torque for driving the gear train influences the frequency of the time-keeping oscillator, as the time-keeping oscillator and the oscillator for driving the gear train are the same.
  • the tuning fork there exists position error. And if one wants to make the daily rate less than 0.2 second it is necessary to make the resonance frequency of the tuning fork over several kHz. But it is very difficult to drive the gear train directly by a tuning fork having such high frequency.
  • Quartz crystal watches having quartz oscillator of several kHz. guarantee a daily rate within 0.2 second.
  • Quartz crystal timepieces usually comprises quartz crystal oscillator, frequency divider, motor and gear train.
  • the frequency divider is inevitable for dividing the frequency of the quartz oscillator of several kHz. into the response frequency of the motor, i.e., several Hz. to several Hz.
  • This invention is particularly characterized in eliminating the frequency divider from quartz crystal timepieces. As a result, it is applicable to Wristwatches requiring small space and a watch of low cost can be realized. Besides, a balancespring oscillator or a synchronized tuning fork can be used instead of motor. As these are conventionally known oscillators which require only small power consumption, they are easy to manufacture it and with low cost. Thus it is very advantageous for making a quartz crystal timepiece compact enough as a wristwatch.
  • FIG. 1 is a block diagram showing one embodiment according to the present invention.
  • FIG. 2 is one embodiment of the block diagram in FIG. 1.
  • FIG. 3 is a cross-sectional view of FIG. 2.
  • FIGS. 4 and 5 are electric circuits of the embodiment shown in FIG. 2.
  • FIG. 6 is a waveform of the embodiment shown in FIG. 2.
  • FIG. 7 is another embodiment of the block diagram shown in FIG. 1.
  • FIG. 8 is a cross-sectional view of the embodiment of FIG. 7.
  • FIG. 9 is a tautochronous curve of the embodiment shown in FIG. 7.
  • FIG. 10 is a device for protecting the balance from outer disturbance.
  • FIG. 1 I is another embodiment of the block diagram.
  • FIG. 12 is a frequency-amplitude curve of the tuning fork of the embodiment shown in FIG. 1 1.
  • FIG. 13 shows another embodiment of the block diagram.
  • FIG. 14 is an embodiment using the block diagram of FIG. 13.
  • FIG. 15 is a waveform of the embodiment shown in FIG. 14.
  • FIG. 1 is a block diagram showing one embodiment of an electric timepiece according to the present invention.
  • I is a relatively high frequency oscillator as the time base.
  • 2 is a relatively low frequency mechanical vibrator, the frequency of which is l/n(n integer) of that of said time keeping oscillator.
  • 3 is means for maintaining the vibration of the mechanical vibrator 2.
  • 4 is means for comparing the vibratory phase of the output from the time keeping oscillator l with that from the mechanical vibrator.
  • 5 is a device which controls the frequency of mechanical vibrator 2 to be l/n(n integer) of that of the time-keeping oscillator l.
  • 6 is a converter which converts the vibratory motion of the mechanical vibrator into rotary motion to operate the indicators and the gear train.
  • the vibratory phase of the output from the time-keeping oscillator having relatively high frequency is compared directly with that from the low frequency mechanical vibrator, the frequency of which is as that of low as the ordinary electric watch and l/n(n integer) of that of said time-keeping oscillator, and said mechanical vibrator is synchronized with the time-keeping oscillator.
  • FIG. 2 is one embodiment according to the invention wherein a balance-spring oscillator is used as the mechanical vibrator.
  • FIG. 3 is a cross-sectional view of said embodiment.
  • 7 is a balance wheel and 8 is a hair spring. Both 7 and 8 form an oscillating system.
  • This oscillating system corresponds to the mechanical vibrator 2 in FIG. 1.
  • Double coil 9 comprising a detecting coil and a driving coil is fixed to the plate 10 and detects the variation in the magnetic flux which passes through the coil. That magnetic flux is generated from the magnets 11 and 12 provided in the neutral point of the oscillation of the balance where the vibration is in static condition. As a result of the flux, the pulsive current is applied to the driving coil. The balance is energized through the electric circuit 13, thus the self-oscillation is maintained.
  • FIG. 4 is one embodiment of the electric circuit 13.
  • 19 is a detecting coil, 20 a driving coil.
  • This type of electric circuit is well known in the electric timepiece using a balance-spring as mechanical vibrator.
  • Self-oscillating means comprising double coil 9, magnets 11 and 12 and electric circuit 13 in FIGS. 2 and 3 correspond to the means 3 for maintaining the oscillation in FIG. 1.
  • 14 is a converter which converts the vibratory motion of the balance into rotary motion to operate the indicators.
  • 15 is a part of the gear train 14.
  • I5 corresponds to the converter and gear train 6 in FIG. 1.
  • 16 is a double coil comprising a detecting coil and a control coil which is spaced by A from the neutral point of the oscillation.
  • I7 is an electric circuit for comparing the vibratory phase of the balance with that of the time-keeping oscillator.
  • 18 is an input terminal from the time keeping oscillator.
  • FIG. 5 is one embodiment of an electric circuit 17 in FIG. 2.
  • 21 is a control coil
  • 23 is an input terminal from the time-keep ing oscillator
  • part A is an amplifier for the detecting signal
  • part B is a flip-flop which compares the vibratory phase of the output from the time-keeping oscillator with that from the balance.
  • the power source is common with that for the selfoscillating circuit shown in FIG. 4
  • FIG. 6 shows a waveform of each point a,b,c in FIG. 5.
  • (i) is a waveform of point a, that is an oscillating pulse series from the time-keeping oscillator.
  • (ii) is a waveform of point b, that is pulse series for detecting the vibratory phase of the balance.
  • (iii) is a waveform of point c, that is the electric waveform of the control pulse, the width of which is equal to the difference of vibratory phase between the output from the time-keeping oscillator and that from the balance.
  • the frequency of the balance is compensated by applying the current through the control coil.
  • the frequency of the time keeping oscillator is 2.5 kHz.
  • the period of the pulse series of (i) is 0.4 m.sec.
  • the pulse period of (ii) is 400 m.sec.
  • the frequency stability of the balance-spring system is usually less than 2X10
  • fluctuation of the pulse series is 0.08 msec.
  • the mechanical vibrator can be easily synchronized. In other words, it is possible to divide it into l/1,000, for the frequency of the time keeping oscillator is 2.5 kHz. and that of the balance is 2.5 Hz. So a frequency di- I vider is unnecessary.
  • the amount of compensation of the balance is nearly proportional to a/A(A z a). So if the driving pulse is applied far from the center of the balance, the amount of frequency compensation of the balance will become larger.
  • the amount of frequency compensation of the balance in theory is maximum at the maximum amplitude A where the speed of the balance is zero.
  • the larger the control power the larger the amount of compensation will be.
  • the control power is determined by the pulse width proportional to the phase difference of vibration and by the peak value decided by the number of turns of control coil 22 and the wire diameter.
  • the ratio 'r/ro(where 'r control pulse width, To driving pulse width) is the ratio of control power and driving power.
  • Driving power is inversely proportional to the quality value of balance.
  • the quality value is inversely proportional to the energy loss of the balance. Therefore the amount of compensation of the balance is proportional to:
  • the frequency range for synchronization is as follows:
  • the double coil 16, electric circuit 17 for comparing the phase difference of the vibration and the input terminal 18 in FIG. 2 correspond to the comparing means 4 and the control means 5 in FIG. 1 respectively.
  • the magnets 11 and 12 in FIGS. 2 and 3 pass over the controlling coil in the double coil 16 four times in one oscillation when the amplitude of the balance is above about 240. By selecting a triggering level of the transitor, the detection only once in one oscillation can be easily gained.
  • the control system shown in FIGS. 2 and 3 the phase-controlling system.
  • FIG. 7 is the other embodiment according to the invention wherein a balance-spring oscillator is used as a mechanical oscillator.
  • FIG. 8 is a sectional view of FIG. 7.
  • the difference from FIG. 2 is that the detecting coil for controlling and that for self-oscillation are the same, and that the control pulse is added at the neutral point of the balance where vibration is in static condition.
  • the coil 24 is a triple one and the detecting coils are included both in the self-oscillating electric circuit 25 and in the electric circuit 26 for comparing the phase of vibration.
  • An iron piece 27 is secured to a member made of Bakelite having weak magnetic permeability and also weak specific electric conductivity at the opposite position to the neutral point of oscillation.
  • the tautochronism shows the characteristic as shown in FIG. 9 such that the watches lose abruptly if the amplitude of the balance increases.
  • the magnets 29,30 and the iron piece 27 act with each other at an amplitude of about I"
  • the tautochronous curve as shown in FIG. 9 can be obtained.
  • the detecting pulse (ii) generates later and so the controlling pulse (iii) becomes smaller than in the steady state mentioned before. Therefore the energy to be added to the balance decreases and the amplitude of the balance becomes small. Then as can be seen from the tautochronous curve in FIG. 9, the operating point moves from the point O to Q and the watch gain abruptly till the next detecting pulse (ii) generates and try to recover its time delay.
  • the width of the next control pulse is smaller than that in steady state but larger than this one. Therefore the operating point moves to the point 0 between 0 and 0,, the watch gains further till the next detecting pulse (ii) generates and try to recover its time delay.
  • the watch gains and the width of the next control pulse is larger than that in the steady state and the energy to be added to the balance increases more than that in the steady state and the amplitude of the balance also increases. Now the operating point moves to the point 0 and the watch loses till the next detecting pulse (ii) generates and try to make the difference from the standard equal to zero.
  • the operating point travels to the point Q and finally settles there. If the watch gains due to the disturbance, the operating point also settles on the point Q finally.
  • the frequency of the balance is synchronized with that of the time keeping oscillator by maintaining the operating point 0 against disturbance and controlling the amplitude constant, at about 207.
  • the efficiency of the control depends on the product of the gradient of the tautochronous curve and the control power. According to the result of an experiment, the frequency range of synchronization of about 30 seconds in daily rate could be obtained by using a time keep ing oscillator of 2 kHz. Therefore it is understood that this system is easy for application.
  • the characteristic of this system is to control the frequency of the balance at l/n(n: integer) of that of a time keeping oscillator by giving a nonlinear characteristic to the balance and keeping the oscillation of the balance always constant.
  • FIG. 11 shows the amplitude-controlling system applied to a tuning fork.
  • This control device comprises the tuning fork 31, magnets 32,33 fixed to said tuning fork, coils 34,35 which act with said magnets, electric circuit 36 for self-oscillation of the tuning fork in which the voltage of the detecting coil forming a part of coil 34 is used as the input and the coil 35 is used as a driving coil, and electric circuit 38 for controlling the tuning fork by supplying an electric current to the controlling coil forming a part of coil 34 comparing the input 37 from a timekeeping oscillator with that from said detecting coil.
  • the frequency of the tuning fork is also synchronized with a time-keeping oscillator in the same manner as the balance.
  • the tuning fork has a nonlinear characteristic owing to the action of the other magnet 39 fixed to said tuning fork and the iron piece 40 secured on the baseplate.
  • FIG. 12 shows said nonlinearcharacteristic, and and a solid line being the tautochronous curve.
  • a mixed line shows the frequency-amplitude curve of the tuning fork exciting.
  • a dotted line shows the frequency of 1/n(n: integer) of that of a time-keeping oscillator. Owing to the same operation as in the case of the balance, the amplitude of the tuning fork is kept constant.
  • the magnet 39 may be used with the magnet 32 or the magnet 33.
  • the process that the oscillation of the tuning fork is transmitted to the gear train and the indicators through the click 41 and the ratchet wheel 42 is exactly the same as conventional tuning fork watches.
  • a converter such as a magnetic escapement may be used.
  • the mechanical vibrator can be easily controlled, for the dividing ratio of the frequency of the tuning fork and a time-keeping oscillator having the frequency of several kiloHertz becomes small.
  • FIG. 13 shows a block diagram of the other examples according to the present invention.
  • the difference from FIG. 1 is that the comparing means, the operating means for self oscillations and the controlling means are united as shown 45.
  • 43 is a time keeping oscillator.
  • 44 is a mechanical vibrator having the frequency of l/n(n: integer) of that of a time-keeping oscillator 43.
  • 46 is a converter and gear train through which the vibration of the mechanical vibrator 44 is transmitted to the indicators.
  • FIG. 14 shows one embodiment of FIG. 13.
  • the voltage induced in a detecting and driving coil which interacts with the magnet 48 fixed on the tuning fork 47 is fed back to the base 52 of transistor 51 through the transformer 50.
  • the transistor As the signal from a time-keeping oscillator has been added to the base 52 from the terminal 53, when the sum of said voltage and said signal attains the trigger level, the transistor is switched on and the current is applied to the coil 49.
  • the current begins to flow, it is applied increasingly owing to the feedback of the transformer 50 during the time of pulse width decided from the electric circuit.
  • FIG. (1) shows the induced voltage wave form of the coil 49. Actually at driving the waveform is varied by the driving current, but for easier understanding the waveform at nondriving is shown here. This is not essential for the explanation of this phenomenon. The same may be said of (iii).
  • (ii) is a signal from a time keeping oscillator.
  • (iii) is a base waveform of the tuning fork at nondriving, which is the sum of (i) and (ii). Taking the trigger level on the position shown by the mixed line, the driving waveform is as shown in (IV).
  • the pulse width 1 is not changed as before mentioned, but it can be seen that the deviation between the neutral point of oscillation and that of the driving pulse changes according to the difference between the phase of vibration of the tuning fork and that of the time-keeping oscillator.
  • the energy to be added to the tuning fork is changed according to the phase of the tuning fork when the driving pulse is added.
  • the interaction between the magnet 54 secured on the tuning fork and the iron piece 55 fixed to the baseplate shown in FIG. 14 can give a nonlinear characteristic as shown in FIG. 12 to the tuning fork. So the frequency of the tuning fork can be controlled to be 1 /n(n integer) of that of a time-keeping oscillator by keeping the amplitude constant, cooperating with the energy change before'mentioned.
  • the characteristic according to this method is to unite the comparing means, self-oscillating driving means and control means and to make the whole composition very simple. According to the results of an experiment, when the crystal oscillator of 16 kHz. is used as a time-keeping oscillator and the tuning fork of 400 Hz. is used as a mechanical vibrator, the frequency range of synchronization, 7X l 0Hz. corresponding to about 1 minute of daily rate could be obtained.
  • a mechanical vibrator having a relatively low frequency such as the balance and the tuning fork etc.
  • a time-keeping oscillator having a relatively high frequency such as a crystal oscillator of several kiloHertz.
  • a time-keeping oscillator having a relatively high frequency such as a crystal oscillator of several kiloHertz.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Electric Clocks (AREA)
US842278A 1968-07-19 1969-07-16 Electric timepiece Expired - Lifetime US3648453A (en)

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JP43050764A JPS4943989B1 (fr) 1968-07-19 1968-07-19

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3766454A (en) * 1969-08-12 1973-10-16 Co Montres Longines Francillon Electronic timepiece
US3806781A (en) * 1971-06-29 1974-04-23 Bernard Sa Electric oscillation maintenance circuit for motor element oscillations
US3812670A (en) * 1971-09-25 1974-05-28 Citizen Watch Co Ltd Converter drive circuit in an electronic timepiece
US3877215A (en) * 1972-12-13 1975-04-15 Ebauches Sa Resonator for a timepiece
US3884034A (en) * 1972-10-11 1975-05-20 Establissements Leon Hatot Sa Quartz synchronised clockwork
US3892066A (en) * 1974-02-27 1975-07-01 Microna Inc Synchronized watch movement
US3937001A (en) * 1972-11-21 1976-02-10 Berney Jean Claude Watch movement driven by a spring and regulated by an electronic circuit
US3965667A (en) * 1973-07-19 1976-06-29 Ebarches S.A. Device for the maintenance and control of the oscillations of the balance wheel of a timepiece
US3970371A (en) * 1973-03-16 1976-07-20 Japan Servo Co., Ltd. Apparatus for chopping light beam
US4010602A (en) * 1974-02-25 1977-03-08 Timex Corporation High frequency reed time governor for a timepiece
US20170045861A1 (en) * 2015-08-11 2017-02-16 Eta Sa Manufacture Horlogere Suisse Mechanical timepiece movement provided with a feedback system for the movement

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3451210A (en) * 1966-07-01 1969-06-24 Benrus Corp System for maintaining oscillations in an electric timing mechanism having an oscillatory element
US3512351A (en) * 1966-09-09 1970-05-19 Smiths Industries Ltd Electrical oscillation generators

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3451210A (en) * 1966-07-01 1969-06-24 Benrus Corp System for maintaining oscillations in an electric timing mechanism having an oscillatory element
US3512351A (en) * 1966-09-09 1970-05-19 Smiths Industries Ltd Electrical oscillation generators

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3766454A (en) * 1969-08-12 1973-10-16 Co Montres Longines Francillon Electronic timepiece
US3806781A (en) * 1971-06-29 1974-04-23 Bernard Sa Electric oscillation maintenance circuit for motor element oscillations
US3812670A (en) * 1971-09-25 1974-05-28 Citizen Watch Co Ltd Converter drive circuit in an electronic timepiece
US3884034A (en) * 1972-10-11 1975-05-20 Establissements Leon Hatot Sa Quartz synchronised clockwork
US3937001A (en) * 1972-11-21 1976-02-10 Berney Jean Claude Watch movement driven by a spring and regulated by an electronic circuit
US3877215A (en) * 1972-12-13 1975-04-15 Ebauches Sa Resonator for a timepiece
US3970371A (en) * 1973-03-16 1976-07-20 Japan Servo Co., Ltd. Apparatus for chopping light beam
US3965667A (en) * 1973-07-19 1976-06-29 Ebarches S.A. Device for the maintenance and control of the oscillations of the balance wheel of a timepiece
US4010602A (en) * 1974-02-25 1977-03-08 Timex Corporation High frequency reed time governor for a timepiece
US3892066A (en) * 1974-02-27 1975-07-01 Microna Inc Synchronized watch movement
US20170045861A1 (en) * 2015-08-11 2017-02-16 Eta Sa Manufacture Horlogere Suisse Mechanical timepiece movement provided with a feedback system for the movement
US9971309B2 (en) * 2015-08-11 2018-05-15 Eta Sa Manufacture Horlogere Suisse Mechanical timepiece movement provided with a feedback system for the movement

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Publication number Publication date
CH528770A (fr) 1972-06-15
JPS4943989B1 (fr) 1974-11-26
CH1103669A4 (fr) 1972-06-15

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