US3807164A

US3807164A - Synchronized quartz crystal watch

Info

Publication number: US3807164A
Application number: US00298109A
Authority: US
Inventors: N Zaisky; L Wiesner
Original assignee: Timex Corp
Current assignee: Timex Group USA Inc
Priority date: 1972-10-16
Filing date: 1972-10-16
Publication date: 1974-04-30
Anticipated expiration: 1991-04-30

Abstract

A highly accurate watch, comprising a quartz crystal time base and a movement controlled by an oscillator regulated to run slightly fast and being periodically connected to the quartz crystal time base. In one embodiment, a pulse counter totals the number of pulses put out by the watch oscillator during its normal operation and activates means to stop the oscillator when a sufficient number of pulses equal to a fixed time period has been reached. A second counter totals the pulses from the quartz cyrstal time reference and reactivates the watch when the number pulses equals the fixed time period thereby wiping out accumulated time errors. In a second embodiment, the output from a balance wheel oscillator and a divided down time base frequency are fed to a flip-flop. The output square wave increases in width due to the frequency difference between the balance wheel and time base and is integrated by an RC circuit. A Schmitt trigger circuit and monostable multivibrator are coupled to the flipflop. so that the trigger circuit is activated for a fixed short time interval and stops the balance wheel through a solenoid. After elapse of the fixed time interval, the balance wheel starts again.

Description

United States Patent [191 Zaisky et al.

7 [451 Apr. 30, 1974 WATCH SYNCHRONIZED QUARTZ CRYSTAL [21] Appl. No.: 298,109

[52] US. Cl. 58/28 R, 331/183 [51] Int. Cl G04c 3/04 [58] Field of Search 58/23 R, 23 A, 23 V, 28 R,

[56] References Cited UNITED STATES PATENTS 3,631,669 H1972 Felrath 58/28 D 3,451,210 6/1969 Helterline et a1, 5 8/26 Primary ExaminerRichard B. Wilkinson I Assistant Examiner--Edith Simmons Jackmon SET 20 BALANCE WHEEL RESET 22 CRYSTAL DMD OSCILLATOR ER [57] ABSTRACT A highly accurate watch, comprising a quartz crystal time base and a movement controlled by an oscillator regulated to run slightly fast and being periodically connected to the quartz crystal time base. In one embodiment, a pulse counter totals the number of pulses put out by the watch oscillator during its normal operation and activates means to stop the oscillator when a sufficient number of pulses equal to a fixed, time period has been reached. A second counter totals the pulses from the quartz cyrstal time reference and reactivates the watchwhen the number pulses equals the fixed time period thereby wiping out accumulated time errors. In a second embodiment, the output from a balance wheel oscillator and a divided down time base frequency are fed to a flip-flop. The output square wave increases in width due to the frequency difference between the balance wheel and time base and is integrated by an RC circuit. A Schmitt trigger circuit and monostable multivibrator are coupled to the flip-flop. so that the trigger circuit is'activated for a fixed short time interval and stops the balance wheel through a solenoid. After elapse of the fixed time interval, the balance wheel starts again.

4 Claims, 3 Drawing Figures mfyzz SYNCHRONIZED QUARTZ CRYSTAL WATCH This is a division of application Ser. No. 144,601 Filed May 18, 1972 and now U.S. PatQNo. 3,756,014.

BACKGROUND OF THE INVENTION The present invention relates to timekeeping devices and more particularly to a synchronized quartz crystal watch.

The use of a quartz oscillator of highly stable frequency in conjunction with a frequency divider to control the frequency of a slave oscillator has long been known, see Jones U.S. Pat. No. 3,110,853. However,

- the application of this desirable means of control to an electric watchhas posed problems. One solution is described in U.S. Pat. No. 3,553,957 whichpertains to a system wherein a counted-down crystal oscillatorfurnishes pulses to a stepping motor driving a display. The system provides correction if the watch is running too fast or too slow.

Various other prior art proposals to exploit the accuracy of a high frequency quartz time base for a watch are found in the U.S. Pat. of Nakai, No. 3,212,252, Imakashi, No. 3,363,410, Schaller, No. 3,282,042 and Helterline, No. 3,451,210. The present invention however, represents-a new and improved arrangement utilizing a quartz crystal time base to control the accuracy of a timekeeping device.

SUMMARY OF THE INVENTION This invention comprises a low frequency oscillator such as a balance wheel which supplies pulses to a first counter. When the counter has totaled a number of pulses corresponding to a fixed time interval, a flip-flop is triggered, activating a solenoid to stop the balance wheel of the timekeeping device which is normally regulated to run fast. A quartz crystal oscillator supplies a divided down output to a second counter which resets the flip-flop when the counter has totaled the number of pulses corresponding to the fixed time interval. The solenoid is deactivated and the timekeeping device starts immediately thereby eliminating any accumulated errors.

In a second embodiment, pulses from a balance wheel and divided down quartz oscillator pulses are fed to a flip-flop which produces a square wave output of increasing width due to the frequency difference between the inputs. The output voltage is integrated by an RC network and a Schmitt trigger circuit is activated when the capacitor reaches the circuits critical level. A solenoid is then activated for a fixed short time interval determined by a monostable multivibrator to stop the balance wheel. After elapse of the time interval, the balance wheel resumes wheel.

Accordingly, it is an object of this invention to provide a new and improved timekeeping device which is synchronized by a quartz crystal time reference.

Another object of this invention is to provide a watch which -is normally regulated to run fast and is synchronized at intervals to eliminate accumulated errors.

A further object of this invention is to provide a unique means for stopping the balance wheel of a watch for a fixed period of time and releasing the balance wheel for oscillation as determined by the quartz synchronizing frequency.

BRIEF DESCRIPTION OF THE DRAWINGS The above andother objects and advantages of the present invention will be moreclearly seen when viewed in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic diagram of a first embodiment of the invention;

FIG. 2 is a schematic diagram of a second embodiment of the invention; and

FIG. 3 illustrates the wave forms at point A on the output of the flip-flop in FIG. '2.

DETAILED DESCRIPTION OF THE INVENTION The invention as shown in FIGS. 1 and 2 pertains to a quartz crystal watch having a balance wheel '10 which is synchronized by a quartz crystal frequency standard 11. Since the details of such a watch, apart from the present invention, are conventional, they will not be discussed in detail herein. It is well-known, for example,-that the balance wheel 10 is coupled to the drive train for the watch and causes movement of the watch hands. A synchronization of the watch in the interest of accuracy may, therefore, be achieved by regulating th movement of the balance wheel 10.

With reference to FIG. 1 of the drawings, the invention includes a balance wheel 10 having a spring finger 12 mounted on the periphery and extending outwardly therefrom. The balance wheel 10 normally oscillates at a low frequency which is fed to a first counter 13. In a typical case, the balance wheel 10 will oscillate at a frequency of (3 e) H,, where e represents the fractional deviation of the balance wheel 10 from the precise frequency. The counter 13 is designed to count up to N pulses which corresponds theoretically to a fixed time interval. The relationship between the number of.

pulses N and the deviation E is such that N l/e.

The counter 13 is connected to a flip-flop 14, the output of which is normally low but goes high when counter 13 reaches N pulses. This activates the solenoid 16 which forces movable member 17 forward into engagement with spring finger 12 to stop the balance wheel 10. Normally, the balance wheel 10 would be halted at or near its maximum excursion.

The high frequency output from the quartz crystal time base 11 is fed through divider 18 to a second counter 19. The quartz frequency may be initially in the 60 KHz range and then divided down to 3.000 Hz by divider 18. When counter 19 reaches N pulses, the solenoid 16 is released and the watch starts immediately. Both counters 13 and 19 are reset when solenoid 16 is deactivated. The watch is designed to normally run fast so that any accumulated timing errors are erased when the balance wheel 10 is stopped. The stopping is momentary so that no problem arises when viewing the watch. It is to be further noted that the counters l3 and 19 may be combined in a single updown counter.

In the embodiment of FIG. 2, which is utilized with a quartz watch construction similar to that of FIG. 1,

pulses from the balance wheel 20 are fed to a flip-flop 21. The normal pulse rate from the low frequency balance wheel oscillator 20 is (3 +e) Hz, where e represents the fractional deviation from the precise frequency due to the fact that the watch is regulated to run fast.

The quartz crystal oscillator 22 supplies high frequency pulses to a divider 23 where they are divided down to a precise output frequency of 3.000 Hz. The quartz oscillator pulses are also fed to the flip-flop 21 and the output therefrom is shown in Fig. 3. It is to be noted that the width of the square wave pulses 24 increase from W to W due to the frequency difference between the balance wheel and crystal oscillator 22.

The output voltage from flip-flop 21 is integrated by the combination of resistor 26 and capacitor 27. When the capacitor voltage reaches the critical level of the Schmitt trigger portion of circuit 28, the solenoid 29 is activated for a short fixed time interval T determined by the monostable multivibrator portion of circuit 28. Stop member 31 is driven into engagement with the spring finger 32 to halt the oscillation after the elapse of time T. While the value of T is not critical, it must be less' than one-sixth second.

During a 24 hour period, the solenoid 29 must be ac-;

tivated to compensate for the number of seconds the watch is regulated to run in the fast direction. The power consumption of the invention isconsidered reasonable under these conditions since no continuous correction is used. For example,'if the watch runs 2 minutes per day fast and the power consumption of the solenoid is 2 milliamperes at 1.5 volts, the current drain will be 24 milliamperehours/year.

The time delay between turn off and turn on is so small as to be imperceptible to the user. The intermittent correction is, therefore, most advantageously employed. The invention as described above can also be used with conventional contact watch designs or electronic watches wherein the driving amplifier is switched on and off. It is to be understood that the above-described arrangements are merely illustrative examples of the application. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

We claim:

1. A synchronized watch comprising:

a low frequency oscillator for driving the watch, said oscillator being regulated to run normally fast producing a deviation from the'precise frequency in the pulses therefrom,

.a high frequency time base,

a divider coupled thereto for reducing the output from the time base to provide highly accurate low frequency timing pulses,

means for combining the low frequency oscillator pulses and the timing pulses to provide a resultant output signal,

means responsive to the output signal to deactivate the low frequency oscillator periodically for a fixed time period and to activate said oscillator at the end of said period thereby intermittently correcting the synchronized 'watch.

2. A synchronized watch in accordance with claim 1 wherein: Y

the low frequency oscillator -wheel, and,

the high frequency time base comprises a quartz oscillator.

3. A synchronized watch in wherein:

the means for combining pulses comprises a flip-flop coupled to the low frequency oscillator and to the frequency divider and,

the means for activating and deactivating the low' frequency oscillator comprises an integrator connected to the output of the flip-flop, a trigger circuit activated when the integrated output reaches a predetermined voltage level, and means for stopping the low frequency oscillator for a predetermined time interval when the trigger circuit is activated.

4. A synchronized watch in accordance with claim 3 wherein:

.the means for stopping the low frequency oscillator fora fixed time period comprises a monostable multivibrator coupled to the trigger circuit, andsolenoid means responsive thereto to engage and stop the low frequency oscillator for a fixed time period determined by the multivibrator.

comprises a balance accordance with claim '1

Claims

1. A synchronized watch comprising: a low frequency oscillator for driving the watch, said oscillator being regulated to run normally fast producing a deviation from the precise frequency in the pulses therefrom, a high frequency time base, a divider coupled thereto for reducing the output from the time base to provide highly accurate low frequency timing pulses, means for combining the low frequency oscillator pulses and the timing pulses to provide a resultant output signal, means responsive to the output signal to deactivate the low frequency oscillator periodically for a fixed time period and to activate said oscillator at the end of said period thereby intermittently correcting the synchronized watch.

2. A synchronized watch in accordance with claim 1 wherein: the low frequency oscillator comprises a balance wheel, and, the high frequency time base comprises a quartz oscillator.

3. A synchronized watch in accordance with claim 1 wherein: the means for combining pulses comprises a flip-flop coupled to the low frequency oscillator and to the frequency divider and, the means for activating and deactivating the low frequency oscillator comprises an integrator connected to the output of the flip-flop, a trigger circuit activated when the integrated output reaches a predetermined voltage level, and means for stopping the low frequency oscillator for a predetermined time interval when the trigger circuit is activated.

4. A synchronized watch in accordance with claim 3 wherein: the means for stopping the low frequency oscillator for a fixed time period comprises a monostable multivibrator coupled to the trigger circuit, and solenoid means responsive thereto to engage and stop the low frEquency oscillator for a fixed time period determined by the multivibrator.