Quartz Crystal Watch

Abstract

A quartz crystal watch comprising a quartz crystal oscillator for generating relatively high frequency signals, a frequency divider circuit for reducing and converting the frequency of the oscillated signals from said oscillator to predetermined frequencies of clock pulse, a pulse width converter for reducing the pulse width of output pulse signals from said frequency divider circuit, a motion transducer for converting the amplified output signals from the amplifier pulse width converter to the corresponding mechanical motions, and a gear train mechanism driven by said mechanical motions, the gear action of said gear train being made to follow the accurate time.

Description

BACKGROUND OF THE INVENTION

This invention relates to a quartz crystal watch and particularly to a quartz crystal watch having a gear train driven in synchronization with the clock pulse of one second cycle which can be obtained by dividing the oscillating frequency from a quartz crystal oscillator having a quartz crystal vibrator. It is known that the oscillating frequency of a metal tuning fork can be utilized as a time standard by converting the vibrations of the tuning fork to a rotary motion by means of a ratchet mechanism, and transferring the resultant rotary motion to a known gear train, thereby working a watch to indicate the proper time. In respect of time accuracy, however, it is desirable to employ a quartz crystal vibrator rather than a metal tuning fork because the former is superior in its oscillating frequency characteristics to the latter. Furthermore, quartz crystal vibrator has other advantages in that, generally speaking, the higher the oscillating frequency, the more accurate and smaller in size. Such advantages make a quartz crystal vibrator suitable for a wrist watch.

On the other hand, the said oscillating frequency signals are too high for the said converter to follow, so that it is necessary to provide a frequency divider circuit, thereby reducing the oscillating frequency in such a degree that said motion converter can easily follow the oscillating frequency. However, there is another problem in that the provision of a frequency divider circuit gives rise to an increased consumption of power, thus badly reducing its usefulness for a wrist watch.

SUMMARY OF THE INVENTION

This invention overcomes the above-mentioned problems. It is one of the objects of the present invention to provide a quartz crystal watch in which the frequency of the oscillated signal from a quartz crystal oscillator is converted through a divider circuit to a frequency of a pulse signal which a converter can easily follow, and in which the pulse width of said pulse signal is reduced through a pulse width converter and the output pulse signal from said pulse width converter is transmitted to the gear train through the above-mentioned converter.

Another object of the present invention is to provide a quartz crystal watch which requires such a small amount of power that an electric cell can be satisfactorily used as a power source.

Another object of the present invention is to provide a quartz crystal watch in which the driving coil of the converter is divided into two parts to miniaturize the driving coil. According to the present invention, there is provided a quartz crystal watch comprising a quartz crystal oscillator for generating relatively high frequency signals, a frequency divider circuit for reducing and converting the frequency of the oscillated signals from said oscillator to predetermined frequencies of clock pulse, a pulse width converter for reducing the pulse width of output pulse signals from said frequency divider circuit, a power amplifier for amplifying the output pulse signals from the said frequency divider circuit, a motion transducer for converting the output signals from the amplifier to corresponding mechanical motions, and a gear train mechanism driven by said mechanical motions, the gear action of said gear train being made to indicate the proper time. The nature, principle, and details of the invention will be best understood by reference to the following description, taken in conjunction with the accompanying drawings in which like parts are designated by like reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing one embodiment of a quartz crystal watch according to the present invention;

FIG. 2 shows an example of circuit diagram of the quartz crystal oscillator of FIG. 1;

FIG. 3 illustrates an example of circuit diagram of the frequency divider circuits of Gi. 1;

FIG. 4 represents an embodiment of circuit diagram of the pulse width convertor of FIG. 1;

FIGS. 5A, 5B schematically show examples of input wave form and output wave form respectively at the pulse width converter of FIG. 4;

FIG. 6 illustrates an example of circuit diagram of the power amplifier of FIG. 1; and

FIG. 7 shows a plan view of the motion transducer of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

One of the embodiments of this invention will be hereinafter explained with reference to the drawings.

In FIG. 1, showing a block diagram of a quartz crystal watch, 11 represents quartz crystal oscillator for emitting relatively high frequency signals of high accuracy, and 12 the frequency divider circuit for suitably reducing and converting the frequency of oscillated signals from the quartz crystal oscillator 11 to the clock pulse of predetermined frequency. The output clock pulse from the frequency divider 12 is relatively large in its pulse width, so that when transmitted as it is to the subsequent stage, a large amount of power is consumed. Accordingly, it is preferred that the output clock pulse width be reduced as much as possible by passing it through the pulse width converter 13. The output pulse signals emitted out of the pulse width converter 13 will then be passed to power amplifier 14, and suitably amplified. The amplified signals are then transmitted to the motion transducer 15 for converting the signals to the corresponding mechanical motions. These mechanical motions produced by the motion converter 15 are then transmitted to the gear train 16, and accurate time can be obtained by the gear action of the gear train 16. The circuit shown in FIG. 2 constitutes back coupling oscillators 11a wherein quartz crystal vibration unit 21, having a natural frequency of e.g. 16,384 hz, is employed and two n-p-n type transistors TR1 and TR2 are connected to the vibration unit 21 with the vibration unit 21 being positioned in between. In this instance the quartz crystal vibration unit will maintain high accurate natural frequency under the temperature in the range of 0.degree. to 50.degree. C. In a temperature range higher than 50.degree. C, however, it is difficult to obtain the high accurate natural frequency, and it is preferred to connect a temperature sensitive capacitor C1 between the vibration unit 21 and common emitter terminal 22 of said oscillating circuit for compensation of any disorders and to connect variable capacitor C2 in the same manner as the temperature capacitor C1 for effecting a fine adjustment to the oscillating frequency as shown in FIG. 2. The oscillating circuit 11a constructed as above is experimentally found to be able to derive oscillating frequency signals having an accuracy of more than 10.sup.-.sup.6 from the output terminal 23 under the temperature ranging -30.degree. C to 80.degree. C.

FIG. 3 illustrates an embodiment of frequency divider 12a of frequency divider 12 shown in FIG. 1. This frequency divider 12a is provided with input terminal 31 in to which the oscillated frequency signals derived from output terminal 23 of the oscillator 11a of FIG. 2 are added. The purpose of providing the frequency divider 12a is to divide the oscillated frequency signals (16,384hz in this instance) from the oscillator 11a, and converting them to a clock pulse of 1 hz i.e., corresponding to one second cycle. For example, the frequency divider 12a comprises two cascade connected astable multivibrators 32a and 32b respectively performing a quarter frequency division, and 10 flip-flop circuits 33a . . . 33j cascade connected to the astable multivibrator 32b and each performing a half frequency division.

The frequency divider 12a as constructed above, can derive output pulse signals of 1/2.sup.14 frequency of the input signals to be applied to the input terminal 31 in from the output terminal 31 out. Accordingly, when the frequency of oscillated signals to be transmitted to the input terminal 31 in from the oscillating circuit 11a is 16,384 hz, pulse signals of 16,384/2.sup.14 = 1 hz can be derived from the output terminal 31 out of the frequency divider 12a.

The pulse width of output signals derived from the above-mentioned frequency divider is generally about one half of the repeating cycle (one second in this instance) of the pulse as shown in FIG. 5A, so that when such wide pulse signals are employed for driving a gear train mechanism, a large amount of power will be wasted, thus making an electric cell undesirable as a power source for a wrist watch.

FIG. 4 illustrates an embodiment of pulse width converter circuit 13 for eliminating as much as possible wasteful consumption of power. Circuit 13 comprises a monostable multivibrator 13a provided with a pair of n-p-n type transistors TR3 and TR4, and its input terminal 41 in is positioned in such a manner that pulse signals as shown in FIG. 5A is applied from output terminals 31 out of the frequency divider 12a. The monostable multivibrator 13a makes it possible to derive output signals having a pulse width determined by the time constant which is the product of resistance of a resistor R.sub.11 connected between the base transistor TR3 and +B power terminal 42, and capacitance of capacitor C.sub.11 connected between the collector of transistor TR3 and the base of transistor TR4. With this construction, as shown in FIG. 5B, the pulse width of output signals to be derived from the monostable multivibrator 13a can be prominently reduced (0.01 second in this instance) in comparison to the input signals, such as shown in FIG. 5A, applied to the input terminal 41 in from the frequency divider 12a, thus reducing the power consumption.

FIG. 6 is an embodiment of power amplifier 14 of FIG. 1, comprising a Darlington circuit 14a having a pair of n-p-n transistors TR5 and TR6. The pulse signals, as shown in FIG. 5B, from the monostable multivibrator 13a, are applied to the base input terminal of the Darlington circuit 14a. Between the collector output terminal and +B power terminal 42, driving coil L is connected for driving a gear train mechanism. Diode D connected between the opposite ends of the driving coil L operates to shunt the counter electromotive force indiced in the driving coil L.

FIG. 7 shows an embodiment of the motion transducer of FIG. 1, wherein a pair of driving coils La and Lb, connected between the collector output terminal of Darlington circuit 14a and +B power terminal 42, are each wound around bar-shaped ends 64a and 64b of respective cores 63a and 63b symmetrically positioned toward both ends of and in parallel with the conductive substrate 61. At the other ends of each core 63a and 63b there are formed semicircular projections 62a and 62b in such a manner that these projections 62a and 62b form an incomplete circular space between them as shown in FIG. 7. At the center of the circular space there is pivotally provided a bar-like permanent magnetic piece 66 in such a manner that both ends thereof are normally positioned at the vicinity of the approaching points of opposing projections 62a and 62b. On the permanent magnetic piece 66, a lever 68 is provided having on both its ends pallet jewels 67a and 67b, and pivotally fixed by the center.

61a and 61b are the curved parts of the substrate 61 and engaged magnetically with the outer ends 64a and 64b of the cores 63a and 63b respectively. When the one second cycle clock pulse as shown in FIG. 5B is applied to the base input terminal of the Darlington circuit 14a, the pulse signals are then transmitted to the driving coils La and Lb and magnetize a pair of cores 63a and 63b, thereby inducing a pair of magnetic poles comprising N-pole and S-pole as shown in FIG. 7 at the facing ends of the semicircular projects 62a and 62b. Thus the induced magnetic poles repel one end of the permanent magnetic piece 66 and simultaneously attract the other end thereof, thus effecting a predetermined rotary moment to the permanent magnetic piece 66. As lever 68 is fixed to the permanent magnetic piece 66, rotary motion of the piece 66 also provides the rotary motion of the lever 68 in the same direction and amount as those of piece 66. The rotary motion of lever 68, on the other hand, provides the rotary motion of escapement wheel 161 of the gear train by the engagement of one of the teeth of wheel 161 to the pallet jewels secured to both ends of the lever 68, at the rate of speed wherein one engagement effects a half pitch of movement in the direction of the arrow 69.

When pulse signals go out, a pair of magnetic poles, once induced at the projections 62a and 62b, disappear and the permanent magnetic piece 66 returns to the stable status, i.e., both ends thereof being positioned at the vicinity of the approaching point of opposing projections 62a and 62b. As the piece 66 returns to the stable status, another pallet jewel fixed on the other end of lever 68 pushes the escapement wheel 161 by a half pitch in the direction of arrow 69, thereby making one second pulse cycle to conform with time indication of one second by rotating escapement wheel 161 by one tooth.

In the quartz crystal watch described above, any time errors that might occur can be easily compensated by adjusting capacitance of variable capacitor shown in FIG. 2.

The invention can be modified within the range which does not constitute departure from the spirit and scope of the invention as set forth in the appended claims.

Claims

What is claimed is:

1. A quartz crystal watch comprising a quartz crystal oscillator for generating relatively high frequency signals, a frequency divider circuit for reducing and converting the frequency of the oscillated signals from said oscillator to predetermined frequencies of clock pulse, a pulse width converter for reducing the pulse width of output pulse signals from said frequency divider circuit to minimize power consumption in the operation of said watch, an amplifier for amplifying the output pulse signals from said pulse width converter, motion converter means including driving coils to which said amplifier output signals are applied, a pivotably mounted lever and magnetic circuit means coupling said lever and driving coils for producing corresponding mechanical motions in said lever in response to said amplifier output signals, and a gear train mechanism driven by said mechanical motions, the gear action of said gear train being made to follow the proper time.

2. The quartz crystal watch according to claim 1, wherein said quartz crystal oscillator includes a quartz crystal vibrator having a relatively high natural frequency, and a temperature sensitive capacitor for compensating temperature coefficient of said vibrator.

3. The quartz crystal watch, according to claim 1, wherein said quartz crystal oscillator includes a variable capacitor for effecting a fine adjustment of oscillating frequency.

4. The quartz crystal watch, according to claim 1, wherein said frequency divider circuit comprises a plurality of flip-flop circuits cascade connected each other.

5. The quartz crystal watch, according to claim 1, wherein said frequency divider circuit comprises a combination of astable multivibrators and flip-flop circuits.

6. The quartz crystal watch according to claim 1, wherein said motion converter means comprises driving coils symmetrically provided in spaced relation, a pair of cores each having a bar-like end inserted into said coils and a semicircular projection on the other end, a bar-like permanent magnetic piece pivotally provided at the center of a circular space formed by said semicircular projections, and a lever having on each end a pallet jewel, said lever being mounted for movement together with said permanent magnetic piece, so that said gear train can be moved at the prescribed rate pitch through said pallet jewels.