US3225536A

US3225536A - Electric clock

Info

Publication number: US3225536A
Application number: US230646A
Authority: US
Inventors: Reich Robert Walter
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-10-15
Filing date: 1962-10-15
Publication date: 1965-12-28
Anticipated expiration: 1982-12-28

Description

Dec. 28, 1965 w, RElCH I 3,225,536

ELECTRIC CLOCK Filed Oct. 15, 1962 3 Sheets-Sheet 1 D/sABLE' @R M Fi QUENCH OSC/LLA TOR g CLOCK I WORK 2/ 6 YNCHR. 0R ENABLE V5 CONTROL /4 IMPEDANCE INVENTOR. ROBERT WALTER RE/CH w Wm QM Affome ya Dec. 28, 1965 R. w. REICH 3,225,536

ELECTRIC CLOCK Filed Oct. 15, 1962 3 Sheets-Sheet 2 i I N/'l g 6 /Z 1; I 63 j 64 /2 /4 65 -H- /2 62 l 7M5 3 l4 INVENTOR. ROBERT WALTER RE/CH Affomeys Dec. 28, 1965 R. w REICH 3,225,536

ELECTRIC CLOCK Filed Oct. 15, 1962 3 Sheets-Sheet 5 Fig. 7

77 L21 lllzl Fig.8

INVENTOR. ROBERT WALTER RE/GH United States Patent 3,225,536 ELECTRIQ CLOQK Robert Walter Reich, Rotackerstrasse 2, Freillurg im Breisgau, Germany lFiled Oct. 15, 1962, Ser. No. 230,646 8 Claims. (Cl. 58-23) This is a continuation-in-part application of my application Serial No. 719,812, filed March 7, 1958 with a priority of March 9, 1957, now abandoned.

The present invention relates to electronic clocks and watches, and more in particular to fully electronically operated and controlled watches and clocks.

Various attempts have been made in the art to provide electronically operated clocks. It has, for example, become known to construct clocks using transistors which are used, however, only as switches. In the emitter or collector circuit of the transistor there is provided the coil for a permanent magnet, the latter inducing a voltage pulse in a second coil. The permanent magnet swings like a pendulum through the solenoid coil. This type of clock has to be started to set the pendulum into swinging motion, and the travelling speed of the pendulum must be considerable in order to bring about an induction in the coil. In circuits of this type, the transistors can be used without any bias of the base in the emitter circuit only. It is therefore impossible to have a stabilization of temperature. This is a great disadvantage in view of the great sensitivity of transistors to changes in temperature in regard to leakage current as well as current amplification. Inaccuracies resulting from the operation of the transistor are inevitable in these known constructions and increase the inaccuracy resulting from the movement of the pendulum, due to friction losses, temperature variations, etc. Moreover, the permanent magnet induces an induction with opposite polarity when entering and leaving the switch coil. Instead of the ideal sine curve of the current in the exciting circuit, a curve is obtained which is composed of the base current, the residual current and the induced current.

Furthermore, the use of transistors in this type of circuit is limited to the pendulum without, however, resulting in a saving of space since the pendulum must have a swinging path and period which are sufiicient to induce a sufliciently great current in the switch coil.

Finally, the transistor connection just described cannot be applied to rotary pendulum clocks or watches or to watches operating with an escapement.

The greatest disadvantage resides, of course, in the fact that it is impossible to effect a stabilization of temperature. The operation of the clock and its accuracy depend directly on the temperature conditioning the leakage current. In a temperature range of, for example, from to 35 Centigrade transistors are conditioned by this temperature in a ratio of from 1:6 to 1:10. A transistor having a leakage current of 100 micro-amperes at a temperature of 20 will have a current of 660 microamperes at a temperature of 35. Since the voltages and currents which can be induced by using small permanent magnets and small coils have about the same magnitude it will be necessary to use permanent magnets and coils with an increased diameter in order to receive a current in the driving coil under all temperature conditions. An additional inaccuracy results if such clocks are brought in the vicinity of substantial iron masses as pipes, radiators, and the like.

Finally, the known constructions are not genuinely electronically operating clocks, as only the spring mechanism is replaced by a magnetic impelling system. The accuracy of the clock still has to be controlled fully mechanically, and in addition, the inaccuracy resulting 3,225,535 Patented Dec. 28, 1965 from the transistor circuit has to be mechanically compensated.

It is an object of the present invention to provide an electronic clock or watch, which can be operated and controlled fully electronically.

It is another object of the present invention to provide an electronic clock or watch, which operates very accurately over a long period of time.

It is a further object of the present invention to provide an electronic clock or watch comprising novel impulse generating means, in which the impulse is entirely independent from factors other than the inherent characteristics of the impulse generating system, and particularly independent from temperature changes.

It is still another object of the present invention to provide an electronic clock or watch, which is susceptible to prolonged operation without disturbance and which has a very long service life.

According to one aspect of the present invention in a preferred embodiment thereof it is suggested to provide a transistor oscillator, preferably of the blocking type, to actuate a clock mechanism either directly or by impelling a mechanical oscillator such as a pendulum or balance wheel, or by periodically rewinding a spring. The transistor oscillator is provided with at least one coil connected in series with a transistor so that unidirectional current pulses of high frequency flow therethrough impelling an armature for actuation of the aforementioned mechanism. The transistor oscillator is provided with circuit means causing it to interrupt itself after one or a few current pulses have flown through the driver coil. The driver coil preferably is coupled to a regenerative feedback loop of the oscillator. In a further embodiment there is provided a controllable circuit element connected between base and emitter electrodes of the transistor for starting the oscillator and means are provided for deriving starting pulses from the clock mechanism. The rate of oscillator actuation is relatively slow, for example, in range of clock pendulum or balance wheel frequencies. While the oscillator frequency itself is higher by several orders of magnitude.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed that the invention, the objects of the invention and further objects and advantages thereof will be better understood from the following description taken in connection with the accompanying drawings in which:

FIG. 1 illustrates a block diagram of the principal clock impelling system in accordance with the invention;

FIG. 2 illustrates a circuit diagram of a first embodiment of the invention showing also a general mode of oscillator triggering;

FIGS. 2a to 2d illustrate various modes of triggering and synchronizing the oscillator of FIG. 2;

FIG. 3 illustrates a modified circuit diagram as compared with FIG. 2 for impelling a pendulum clock;

FIG. 4 illustrates a circuit diagram of a further embodiment of the invention showing specifically a winding mechanism for a clock norm-ally driven by a spring;

FIG. 5 illustrates a modification of the system of FIG. 4;

FIG. 6 illustrates a novel impelling system of a specific balance wheel structure;

FIG. 7 illustrates another embodiment of the invention using an oscillator of the self-quenching type for directly driving a clockwork;

FIG. 8 illustrates a further embodiment of the invention using a transistor blocking oscillator supplemented by a second transistor to form a multivibrator; and

FIG. 9 illustrates a simplified clock winding mechanism.

Turning first to FIG. 1, there is shown the principal system of the present invention. Numeral 1 denotes an oscillator, particularly a transistor oscillator of the free running type, oscillating at a relatively high frequency of 1000 c.p.s. The oscillator has among its elements a coil 11 serving as output coil for impelling an armature 21 pertaining to a clock work on mechanism 2. The armature 21 may either drive the hands of the clock directly or it may periodically impel a mechanical oscillator such as a balance wheel with escapement spring, a pendulum or a flywheel, or lever 21 may periodically load a spring which in ttun then drives the hands of the clock. It is an important feature of the invention, that the oscillator 1 produces unidirectional current pulses in coil 11 of a frequency which is entirely independent of the frequency with which the impelling occurs. The frequency of impelling i.e. of armature actuation will preferably be in the range of 1 c.p.s. Thus, the oscillator output is a train of pulses or pulse groups with the pulse frequency itself being determined by the transistor oscillator alone while the train frequency i.e. the frequency of pulse group occurrence determines the rate of impelling. This requires that the oscillator -1 be interrupted soon after it has started. Box 3 denotes a network or device which interrupts the oscillator 1 after it has started to deliver pulses to driving coil 11. The self interruption or disabling may be produced by the oscillator 1 itself (arrow 4), in that the oscillator upon starting triggers its own interrupting control by feed back or quenching action. Element 3 may structurally be incorporated in the oscillator in that the latter is normally kept disabled, but is enabled periodically as will be described below.

Depending upon the kind of oscillator it may be that it is capable by itself to restart, in which case no further element is required. It may be desirable, however, to synchronize the impelling action, in which case a control signal is derived from the clock work 2 and is fed a synchronization signal to the oscillator (control 5). If the oscillator 1 is not of the self starting type, then the control 5 can also serve as trigger. It is an important feature, that the synchronization pulses, which eventually are also trigger pulses, are not amplified by oscillator 1, but the current in coil 11 for impelling the clock work is solely determined by the transistor oscillator itself and not by the amplitude of any input pulse thereof. This way constant impelling forces are ensured independent from the strength of any triggering or synchronizing signals. In the following several examples will be described how the principal system of the invention can be practiced advantageously.

Proceeding now to FIG. 2, there is shown a transistor 12 having its emitter electrode connected to the positive pole of a D0. voltage source 13, for example a battery, through a resistor 14. The collector electrode is connected to the negative pole via driver coil 11; the transistor being of the pnp type. In case of an npn transistor, the polarity of the voltage source simply has to be reversed. The base electrode of transistor 12 is connected to a capacitor 15 which in turn is connected to a feed back coil 16, the latter being connected to the plus pole of source 13.

Coils

11 and 16 are inductively coupled and preferably wound on a common core, they define a feed back transformer 19. The transformer 19 is of the miniature type having a high grade magnetic material such as ferrozcube (produced by Phillips, Holland) or siferrit (produced by Siemens, Berlin).

The elements as described thus far constitute a blocking oscillator. There is a third coil 17 mounted on the transformer core, which coil 17 is short-circuited by a resistor 18. Numeral 18 can also represent the ohmic resistivity of coil 17 itself. Coil 17 has to have a high number of windings, which is about the thirty-to-fifty fold of the number of windings of

coils

11 and 16. The transistor is temperature stabilized by means of the resistor 14 in conjunction with an impedance 5'. The impedance 5' is shown as block since in this example it may be controlled for synchronization from the clock work '2.

The oscillator as described thus far operates as follows. Assuming that a small emitter current is flowing, there is an increasing collector current flowing through coil 11. The rising flux induces a negative voltage in coil 16 at capacitor 15 so that the base potential is made more negative; correspondingly the emitter and collector current increases, and by regenerative action the collect-or current is soon driven to saturation. After the flux in transformer 19 ceases to change, the voltage across coil 16 drops to zero. The capacitor has been charged, so that the base potential now is positive with respect to the emitter, thus blocking transistor 12. The decreasing flux in the transformer reverses the induced voltage across coil 16 so as to regeneratively turn transistor 12 off. Thus, there is produced in coil 11 a high, needle shaped, unidirectional current pulse acting upon armature 21 for impelling drive 2. The direction and strength of this pulse is only dependent upon the dimensions and characteristics of the oscillator circuit elements employed. It is therefore possible to proportion the various elements so that the pulse produced is suflicient to attract the armature for impellin-g the clock work. The short-circuited coil 17 prevents the oscillator from starting anew. In this case, therefore, the oscillator 1 requires a trigger pulse which is carried out by impedance control. This is explained in connection with FIGS. 2a to 2d.

In FIG. 20 it is shown that the impedance between base and emitter electrodes of transistor 12 is a coil 5a. Suppose the clock is a pendulum clock, then one simply mounts a small permanent magnet 22 on the pendulum and magnet 22 is positioned so that it passes coil 5a when the pendulum swings. Thus, there will periodically be induced a negative voltage pulse in coil 5a, momentarily rendering the base electrode of transistor 12 negative relative to the emitter electrode, starting the oscillat-or.

It was said above, that the mechanical oscillator (here pendulum) frequency is small as compared with that of the electronic oscillator. It follows, that the voltage induced in coil 5a keeps the base voltage negative for longer than the transistor oscillator period. Accordingly, the oscillator is enabled to produce a pulse group until there is no more negative base bias, at which time the 'attenuating action of short circuited winding 17 (FIG. 2) prevails. The strength of the oscillator pulses in driver coil 11 does not depend on the strength of the trigger voltage in coil 5a.

FIG. 2b shows, that the trigger and synchronizing principle described in connection with FIG. 2a can also be used when the clock operates with a balance wheel as mechanical oscillator. There is shown a balance wheel 26 with escapement spring 2'7 and carrying small permanent magnets 28. These magnets induce the trigger voltage in coil 5b in a manner similar as was described in connection with FIG. 2a. Driver coil 11 may be arranged so as to impel one of the magnets 23 when the oscillator is triggered.

If for example, there is a lamp 23 in the clock, for example for illuminating the hands or the digits, one can provide for a light path governed by a diaphragm 24 which pertains to the clock pendulum thus controlling the light reaching a photoelectric receiver 25 such as a photo diode or phototransistor which is connected between emitter and base electrodes of transistor 12, so as to produce a negative starting or trigger pulse at the base electrode whenever the light is permitted to enter element 25.

The diaphragm can also be mounted on a spring-winding lever for triggering the oscillator whenever rewinding is required.

FIG. 2d shows, that the base electrode of transistor 12 can be connected to a capacitor 29. After transistor cut off the blocking charge is distributed on capacitor 15 and capacitor 29. Since

capacitors

15 and 29 cannot discharge after transistor cut off except through leakage current, the oscillator remains blocked. One plate of this capacitor 29 can be connected to the pendulum or to a rewinding lever of the clock so as to periodically vary the capacitance. The corresponding change in charge can be effective as negative trigger pulse at the base electrode to restart the oscillator.

Proceeding now to FIG. 3, there is shown how impelling and oscillator triggering can be combined in a pendulum clock. Elements 11 to 19 correspond to those previouly described. There is further shown a clock work 2 with gear wheels 31 constituting a transmission gear and hands 32 driven via a ratchet wheel 33. Ratchet wheel 33 is rotated stepwise by pendulum 34 having a pawl 35 and carrying armature 21. There is suspended a permanent magnet 36 periodically entering and leaving a solenoid coil 37 which is connected between base and emitter electrodes of transistor 12. Accordingly, there is a voltage induced in coil 36 the polarity of which with respect to its emitter-base connection can be selected so that a negative base trigger pulse for the oscillator is produced.

The transistor oscillator operates as was described in connection with FIG. 2 so that the impelling pulse in coil 11 attracts armature 21. The oscillator produces pulses as long as there is a negative trigger or enabling voltage at the base electrode from coil 37. The oscillator is triggered and then the magnet 36 moves out of the coil 37.

In most pendulum clocks, the clock cannot be started automatically as the oscillation of the pendulum has to be started. This inconvenience can be avoided by providing a small push button 38 connecting for a short period the capacitor 15 in the base circuit of transistor 12 to the negative pole of the voltage source 13, which results in the creation of an impulse in driving coil 11, thereby starting the clock. This is, of course, unnecessary in escapement watches as the escapement is started when setting the watch whereafter the electronic control sets in and is sufficient to secure the further operation of the clock.

Proceeding now in FIG. 4, there is shown a modification of the devices as compared with the aforementioned described systems. It is assumed, that clock drive 2 here operates with a spring normally driving the clock, while periodically the spring is reloaded. In this case the transistor oscillator does not cooperate directly with a mechanical oscillator (balance wheel with escapement spring, or pendulum). In FIG. 4, there is first shown again the oscillator transistor 12, connected as aforedescribed. There is now a winding lever 41 carrying a small permanent magnet 42 which may plunge into solenoid coil 43. Winding lever 41 has a pawl 45 for actuating a ratchet wheel 46 which in turn rewinds and loads a clock spring. Coil 43 is connected between base and emitter electrodes of transistor 12. Winding lever 41 supports a core-armature 44 which may or may not be also a permanent magnet.

Whenever the spring of the clock has discharged and has to be reloaded, lever 41 drops plunger magnet 42 into coil 43. A negative voltage potential is produced by induction at the base electrode of transistof 12 and the blocking oscillator produces unidirectional pulses in driver coil 11 as long as this negative voltage prevails across coil 43. Armature 44 is attracted and lever 41 correspondingly winds the clock spring. The immediate pulling out of magnet 42 from solenoid coil 43 reverses the base bias interrupting the blocking oscillator. Only when again a reloading of the clock spring is required, magnet 42 drops into coil 43 and a new group of impelling pulses is produced in driving coil 11. The frequency of this winding process may be at the order of once every one or two minutes.

The rewinding arrangement of a clock spring as shown in FIG. 5 differs from that in FIG. 4 in that the armature and the excitor magnet are one and the same element, and driver coil 11 is compared with FIG. 4 is wound so that the current pulses produce a magnetic repelling force actuating lever 41 and ratchet wheel 45 to rewind the spring. Again, reversal of the movement of magnet 51 biases the transistor 12 to cut off.

Proceeding now to FIG. 6, there is shown a system for impelling an escapement mechanism with a special balance wheel.

The balance wheel here is composed of two

segments

61 and 62, preferably made of permanent magnetic steel. They are interconnected by a spoke 63 to which is attached the escapement spring 64. Exciter coil 65 is again a solenoid coil cooperating with magnet-segment 62 and being connected between base and emitter electrodes of transistor 12. Driving coil 11 im-pels the balance structure in either attracting or repelling magnet segment 61. The mode of impelling can be made as is deemed best for a particular structure. It is apparent, that the relative position of stationary coil 65 with respect to the oscillatory path of the balance wheel determines the time during which the transistor oscillator is permitted to oscillate.

In FIG. 7 is illustrated a different type oscillator used for directly driving a clock in steps, with the step frequency being solely determined by the transistor oscillator itself. Elements 11 to 16 correspond to similarly designated elements of the previously described figures. There is, however, a second feed back loop comprising a series connection of a capacitor 72 and of a coil 73 Wound on the feedback transformer 19. This second feedback loop provides for a self quenching oscillator. There is no exciter coil required in this instance for triggering the oscillator, since the clock is driven at quench frequency. Armature 74 has a pawl 75 engaging a ratchet wheel 76 which in steps moves the hands 77 of the clock via a transmission gear 78. Alternatively, an eXciter coil could be used for reasons of synchronizing and phaselocking the low quench frequency with the mechanical frequency in the clock in case a balance wheel or a pendulum is used.

This oscillator now produces pulse groups at a repetition rate depending upon the said second feedback loop.

It should be mentioned, that the elements 17 and 18 of the previously described arrangements can be substituted by this second feedback loop 72-73 as shown in FIG. 7. The quench frequency can be made as low as desired so as to determine the repetition rate of impelling by means of high frequency pulses of the blocking oscillator. Any control element connected between base and emitter electrodes then does not trigger the oscillator but synchronizes the quench frequency to the clock frequency.

In FIG. 8 there is shown an oscillator for impelling a clock work wherein the accuracy can be adjusted solely within the oscillator not even requiring any synchronization. The blocking oscillator arrangement is basically

similarsee elements

11, 12, 13, 15, 16 and 19. However, a second transistor, 81 has been added to govern the oscillator action. The base electrode of transistor 81 is connected to the collector electrode of transistor 12 via a capacitor 82. The base electrode of transistor 81 is further connected to the plus terminal of source 13 via a third coil 83 coupled to

coils

11 and 16. The collector electrode of transistor 81 is (1) connected directly to the base electrode of transistor 12 and (2) is connected to the negative pole of source 13 via an adjustable resistor 84.

Assuming transistor 81 being conductive, the transistor 12 is correspondingly non-conductive, capacitor 82 charges slowly toward a positive base bias until transistor 81 is cut off; the then negative voltage potential of the collector of transistor 81 is directly applied to the base electrode of transistor 12 and the latter starts to conduct. The current through coil 11 is immediately regeneratively increased by feedback action of coilcapacitor loop 1615 rapidly driving the transistor 12 to saturation. correspondingly capacitor 82 discharges. Upon blocking action by capacitor 15 rendering transistor 12 temporarily non-conductive, discharge of capacitor 82 ceases. The blocking oscillator still continues, causing capacitor 32 to discharge in steps until transistor 81 is rendered conductive again which in turn renders transistor 12 non-conductive. A recharge of capacitor 82 reverses again the state of conduction of the two transistors. Recharging of the capacitor 82 reduces the collector current of transistor 81. Thus, the amount of resistivity adjusted at resistor 84 determines at what state transistor 12 is rendered conductive. This, accordingly determines the period of time which elapses between two pulse groups etfective in coil 11 for impelling the clock drive 2. Coil 83 is short circuited when transistor 81 becomes conductive and this prevents the oscillator from starting until transistor 81 has been cut off.

FIG. 9 illustrates a more simplified impelling system of the invention. This is devised particularly for more simple watches. There is shown a winding lever 91 cooperating with a ratchet wheel 92 and having an iron core 93. Furthermore, lever 91 has a movable contact 94a connected electrically to the negative pole of voltage source 13. A transistor 95 has a coil 96 inserted into its collector circuit, which coil 96 is likewise connected to the negative pole. There is a capacitor 97 of very large capacitance connected between base and emitter electrodes of transistor 95 and the base electrode is connected to a stationary contact 94b via a resistor 98. When the spring of the clockwork needs reloading, lever 91 moves up thus connecting capacitor 97 to the negative voltage source terminal, rendering transistor 95 conductive so as to attract core 93. The corresponding pivot ing of lever 91 rewinds the clock, and contacts 94a and 94b disengage.

In all embodiments described above, the current pulses in the driver coil are entirely independent from the influence of temperature. The leakage current does not become effective, since the collector current and the collector voltage always decreases to the value of the knee-voltage at every blocking step within the oscillator. Since the driving coil is positioned in the collector circuit there is normally no current flow of any consequence through this coil. The driving pulse is so short and sets in and stops so abruptly that during its duration there is a substantially even flow of current.

The current supply for electric clocks operated with pulses generated in the circuits as described above can be easily produced and sold at low cost; the voltage of a dry cell battery or a small accumulator cell is entirely suflicient. The lifetime of such current supply means extends over many years and it is practically limited only by the self-discharge of the cells.

Even in very flat wrist watches the electric power supply does not ofier a considerable problem. The very small accumulators which are presently otfered in the market can be used and operated for months, without recharging. The transistors and the very few other electric elements are all of very small size, about in the order of a needle or a match head.

The current consumption of the electronically operated and controlled clock of the present invention is extremely small and it will therefore be found to be of particular advantage to use as a current supply very small gastight accumulators or batteries, for example acorn cells. These batteries are gas-proof so that neither gases nor acid canpenetrate through the cells. Preferably, the electric supply unit also comprises a recharging circuit which forms part of the supply unit mounted in the clock casing. The recharging can be effected by a small plug at the outside of the cases and with current obtained from the mains. It will be sufficient if this is done for a few hours about once every year. It is thus possible to operate the clock over a period of many years without having to exchange spare parts. Since the lifetime of the transistors is virtually nearly unlimited, there will hardly be any disturbance in the orderly operation of the clock.

The invention is not limited to the embodiments described above but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be covered by the following claims.

What is claimed is:

1. In an electronic clock having a clock driving mechanism including an oscillatory actuating and force transmission element for driving the said mechanism, the combination comprising: a transistor; a driving coil connected to the emitter collector path of said transistor; a feedback loop connected to the base electrode of said transistor and including a capacitor and a second coil coupled to said driving coil so as to define a blocking oscillator; means including controllable impedance means independent of the coils in the collector circuit of said transistor and connected to said base electrode for periodically enabling and disabling said oscillator at a rate corresponding to the rate of oscillation of said mechanism; and an armature cooperating with said driving coil and connected to said element for actuation of said mechanism in response to driving pulses in said driving coil.

2. In a clock as set forth in claim 1; said impedance means including a third coil coupled to said driver coil, and a second capacitor connecting said third coil to said base electrode.

3. In an electronic clock having a clock driving mecha nism including an oscillator actuating and force transmission element for driving said mechanism, the combination comprising: a transistor; a driving coil connected to the emitter-collector path of said transistor; a feedback loop connected to the base electrode of said transistor and including a capacitor and a second coil coupled to said driving coil so as to define a blocking oscillator; means for periodically enabling and disabling said oscillator at a rate corresponding to the rate of oscillation of said element, and including controllable impedance means independent of the coils in the collector circuit of said transistor and connected between base and emitter electrodes of said transistor; means actuated periodically by said mechanism for controlling said impedance means; and a armature cooperating with said driving coil and connecting to said force transmission element for actuation of said mechanism in response to driving pulses in said coil.

4. In a clock as set forth in claim 3, said controllable impedance means comprising a photoelectric receiver, there being a diaphragm connected to said mechanism for pcriodically permitting light to enter said receiver.

5. In a clock as set forth in claim 3, said controllable impedance means and controlling means comprising a capacitor, one plate thereof being linked to said mechanism.

6. In an electronic clock having a transmission gear and a mechanical oscillator for driving the hands, the combination comprising: a transistor oscillator including a transistor and a driving coil connected to the transistor and including circuit means connected for normally disabling the transistor oscillator in response to the production of oscillations therein; an armature connected to said mechanical oscillator and cooperating with said driving coil for impelling said mechanical oscillator; and oscillator including a trigger coil between the base and emitter of said transistor; and a permanent magnet on said mechanical oscillator movable relative to said trigger coil for periodically triggering said transistor oscillator, the ranges of frequencies of said mechanical oscillator and of said transistor oscillator being apart by several orders of magnitude.

7. In a clock as set forth in claim 6 in Which said mechanism oscillator includes a pendulum, and said magnet is mounted on the pendulum.

8. In a clock as set forth in claim 6, said mechanical oscillator comprising a balance wheel with escapement spring armature and said magnet being part of said balance wheel.

References Cited by the Examiner UNITED STATES PATENTS Wold 58-23 Anderson 331-411 Shaull 318128 Sargeant 58--23 Van Overbeek 331-116 Reich 318128 10 LEO SMILOW, Primary Examiner.

JOSEPH P. STRIZAK, ROBERT L. EVANS, Examiners.

Claims

1. IN AN ELECTRONIC CLOCK HAVING A CLOCK DRIVING MECHANISM INCLUDING AN OSCILLATORY ACTUATING AND FORCE TRANSMISSION ELEMENT FOR DRIVING THE SAID MECHANISM, THE COMBINATION COMPRISING: A TRANSISTOR; A DRIVING COIL CONNECTED TO THE EMITTER COLLECTOR PATH OF SAID TRANSISTOR; A FEEDBACK LOOP CONNECTED TO THE BASE ELECTRODE OF SAID TRANSISTOR AND INCLUDING A CAPACITOR AND A SECOND COIL COUPLED TO SAID DRIVING COIL SO AS TO DEFINE A BLOCKING OSCILLATOR; MEANS INCLUDING CONTROLLABLE IMPEDANCE MEANS INDEPENDENT OF THE COILS IN THE COLLECTOR CIRCUIT OF SAID TRANSISTOR AND CONNECTED TO SAIDBASE ELECTRODE FOR PERIODICALLY ENABLING TO AND DISABLING SAID OSCILLATOR AT A RATE CORRESPONDING TO THE RATE OF OSCILLATION OF SAID MECHANISM; AND ARMATURE COOPERATING WITH SAID DRIVING COIL AND CONNECTED TO SAID ELEMENT FOR ACTUATION OF SAID MECHANISM IN RESPONSE TO DRIVING PULSES IN SAID DRIVING COIL.