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Publication numberUS3724200 A
Publication typeGrant
Publication dateApr 3, 1973
Filing dateFeb 1, 1971
Priority dateJan 30, 1970
Also published asCA939911A, CA939911A1, DE2004076A1
Publication numberUS 3724200 A, US 3724200A, US-A-3724200, US3724200 A, US3724200A
InventorsS Donner
Original AssigneeKieninger & Obergfell
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electronic clock with low power consumption
US 3724200 A
Abstract
An astable multivibrator, driven by a solar battery or other long-term current supply, pulses an electromagnetic stepping drive for intermittently winding up a coil spring which powers a mechanical clockwork. The spring, connected to its stepping drive via a one-way coupling permitting manual rewinding, has one end secured to a leadscrew and has its other end tied to a nut thereon so that the degree of unwinding is indicated by the axial position of the nut on the lead screw. When the spring has been tightened to a predetermined extent, the nut trips an electric switch or a lever to prevent overwinding by disconnecting the multivibrator, arresting the stepping drive or decoupling that drive from its load.
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United States Patent. 1

Donner 541 ELECTRONIC CLOCK WITH LOW [21] Appl. No.: 111,264

[30] Foreign Application Priority Data 111 3,724,200 [451 Apr. 3, 1973 FOREIGN PATENTS OR APPLICATIONS 12/1956 Germany ..58/41A 11/1948 Italy ..58/40 Primary Examiner--Richard B. Wilkinson Assistant Examiner-E. C. Simmons Jackmon Attamey-Kar1 F. Ross 57 ABSTRACT An astable multivibrator, driven by a solar battery or other long-term current supply, pulses an electromagnetic stepping drive for intermittently winding up a coil spring which powers a mechanical clockwork.

Jan. 30, Germany ..P The pring onne ted to tepping drive via a oneway coupling permitting manual rewinding, has one [52] U.S. Cl. .58/41 R, 58/83 end secured to a leadscrew and has its other end tied [51] Int. Cl. ..G0lc 9/00, G04b 9/02 to a nut thereon so that the degree of unwinding is in- [58] Field of Search 58/23 R, 40, 41 R, 41 A, 41 B, dicated by the axial position of the nut on the lead 5 /46 43 3 screw. When the spring has been tightened to a predetermined extent, the nut trips an electric switch [56] References Cied or a lever toprevent overwinding by disconnecting the multivibrator, arresting the stepping drive or UNITED STATES PATENTS decoupling that drive from its load.

3,474,618 10/1969 Klinck ..58/41 R 21 Claims, 4 Drawing Figures Balancer a Clockwork f/ Rafcher Coupling Sfepping Drive Pulse Generator PATENIEDAPM Inn 3.724200 SHEET 1 [1F 3 Balancer I Clockwork D force Sforer Follower s V f% I6--EE Oielrrfurfzning 14;. Ratchet "/P Coupling fife n Dr've 2 PP 9 Pulse Generator SOLAR BATTERY Z1 Z: Z: Zu 5m Siegmar Donner INVENTOR.

BY l Kw.

Allr'une y PATENTEDAPR 3 197a SHEET 3 [1f 3 The present invention relates to a clock or other timepiece with a long-term or regenerative electric power supply, such as a solar battery or a set of airdepolan'zed cells.

Electrically powered timepieces of conventional design, using, for example, a nickel-cadmium battery with a photoelectric circuit as a current supply, have various drawbacks including limited storage capacity per unit of weight, poor efficiency requiring relatively long charging periods, and a tendency to deteriorate beyond recovery upon prolonged discharge without recharging. Thus, photoelectrically regenerated accumulators are particularly vulnerable to extended periods of darkness or reduced illumination, e.g., when stored in vaults or transported in crates, so that special precautions must be taken to insure their operative condition upon subsequent exposure to light.

An object of the present invention, therefore, is to provide an improved timepiece of this general character which avoids the aforestated drawbacks.

A more particular object is to provide means in such a timepiece for efficiently storing, over an extended period, the energy delivered by a solar battery or the like during times of abundant supply.

It is also an object of this invention to provide means for conserving the available electric energy for extended periods.

These objects are realized, pursuant to the present invention, by the provision of a mechanical force storer which powers the clockwork of the timepiece and which is intermittently reloaded by a mechanism ineluding an electrodynamic stepping drive connected to an electronic pulse generator for periodic energization thereby. The mechanical force storer is provided with a follower which, whenever the force storer reaches a predetermined state of loading, trips a device for disconnecting the pulse generator from its power supply or otherwise blocking the reloading mechanism to prevent overloading. I

Even after protracted idleness, such a timepiece can be put into service almost immediately, either by regenerating its power supply or by manually reloading its force storer pending such regeneration. The pulse generator may be an astable multivibrator, preferably consisting of two cascaded transistors of opposite conductivity type, which draws virtually no current during the intervals between pulses. The stepping drive advantageously comprises an electromagnetic coil in series with the second-stage transistor and a swingable armature in the field of that coil, the armature being preferably spring-loaded so as to have a natural frequency substantially coinciding with the operating frequency of the multivibrator.

To translate the reciprocation. of the swingable annature into unidirectional rotation of a shaft, a one-way coupling such as a pawl-and-ratchet drive may form part of a transmission linking that armature with the input end of the force storer. This one-way coupling, or a similar one such as an overrunning clutch in cascade therewith, allows the shaft to be manually turned by a key or the like to reload the force storer independently of its electrically powered stepping drive.

The mechanical force storer is preferably a spring,

although a weight of the type used in pendulum clocks would also be suitable. In an embodiment preferred for its compactness, the spring is a spirally coiled band having one extremity secured to a leadscrew centered on its axis and having its other extremity coupled with a nut riding on that lead-screw. If the pulse generator operates at its normal rate consistent with a charged supply battery, the input end of the spring is rotated more rapidly (in a tightening sense) than its output end and the nut moves axially on the leadscrew until it trips the associated blocking device. The latter may be an electric switch connected as a circuit breaker in the input or in a feedback path of the multivibrator; it could also be a lever interposable in the path of the electromagnetic armature or coacting with its stepping pawl to decouple it from the associated ratchet, thereby minimizing the energy consumption of the pulse generator.

The invention will be described in detail hereinafter with reference to the accompanying drawing in which:

FIG. 1 is an overall block diagram of a system according to the invention;

FIG. 2 is a partly diagrammatic, partly perspective view of a physical mode of realization of the system of FIG. 1; v

FIG. 3 is a view similar to FIG. 2, illustrating another embodiment; and

FIG. 4 is a perspective view of a modified part of the system of FIG. 3.

Reference will first be made to FIG. 1 which shows the principal components of a system embodying this invention. It comprises a d-c power supply in the form of a solar battery Z, constituted by several series-connnected selenium cells 2, Z and a capacitor C', connected thereacross. This power supply feeds an electronic pulse generator 1 periodically energizing an electromagnetic stepping drive 2. The latter intermitten tly reloads, via a ratchet coupling 11 and an over running clutch 15 in series therewith, a mechanical force storer 3 powering a clockwork 4 under the control of a conventional balancer 5. A transmission 6 connects the clockwork 4 with a timepiece including a minute hand 7, an hour hand 8 and a clock face 9.

Force storer 3 also entrains a follower 10 designed to disable the reloading mechanism 1, 2, 11, 15 whenever the stored force reaches a predetermined maximum. As diagrammatically indicated, the deactivation may be accomplishedthrough one or more of several blocking means 12 14, i.e., with de-energization of the pulse generator 1 via a switching circuit 12, immobilization of the stepping drive 2 by way of an abutment 13 and/or disengagement of the ratchet coupling 11 with the aid of an inhibitor 14.

Finally, the transmission linking the stepping drive with the force storer 3 includes a shaft with an extension 16 which is normally driven by the overiunning clutch 15 but can be independently rotated with the help of a suitable tool for a rapid loading of the force storer 3 to restart the clockwork 4 or to prevent its stoppage in the case of failing electric energy reserve.

FIG. 2 shows details of the elements broadly described with reference to FIG. 1.

The pulse generator 1 illustrated in FIG. 2 comprises a PNP transistor T and an NPN transistor T in emitter joined through aresistor R to the base of transistor T the latter has its emitter tied to the negative terminal of source Z and its collector returned to the positive terminal of that source through an elec 'tromagnetic coil 17 forming part of stepping drive 2. A

feedback path from the collector of the second-stage transistor T to the base of first-stage transistor T comprises a condenser C in series with a resistor R this path also including conductors 12 terminating at a normally closed switch 68. Circuit 12 (indicated diagrammatically in FIG. 1) isfurther connected to the junction of a pair of high-ohmic resistors R R serially connected across power supply Z, C to bias the base of transistor T to a value which would normally render this transistor conductive, thereby unblocking the transistor T with consequent energization of coil 17 by a pulse which is differentiated by the condenser C and the resistor R to drive the base of transistor T still more negative; this results in instant saturation of both transistors. As the condenser C discharges, through coil 17' and transistor T in series, the driving current for transistor T decreases'and the feedback of its positive-going collector potential through condenser C to the base of transistor T rapidly cuts off the' two transistor stages. Thus, the duration of the pulse is determined primarily by the capacitance of condenser C and the resistance of coil 17 whereas the recovery interval depends on the time constant of impedances C R The high value of resistors R R prevents any substantial drain of battery Z in the 'nonconductive state of the transistors during which the condenser C, is recharged at a rate determined by its preferably high capacitance and the internal resistance of the battery. The illustrated multivibrator may begin to function with a voltage difference of as little as 0.8 V across this condenser.

Coil 17 forms part of a solenoid with a core 18 having a bifurcate end 24 articulated to a swingable arm 23 which is suspended from a mounting plate 19 by a pair of parallel leaf springs 25, a swing plate 22 and a joint 21. Mounting plate 19 is connected with the clock housing, not shown, by a screw 20. Elements 18 and 2124 constitute an armature which together with springs 25 defines an oscillatory system whose natural frequency should equal or at least approximate the repetition frequency of multivibrator 1 for optimum energy transfer. Arm 23 carries a cross-pin 26 engaged by a pair of looped ends 28 of a U-shaped wire 27 serving as a stepping pawl for a ratchet 29 which also coacts with a retaining pawl 30 in the form of a leaf spring depending from a fixed support 31. Ratchet wheel 29 is rigid with a pinion 32 drivinga gear 33 which in turn entrains a pinion 34 in mesh with a gear 35, this gear train forming part of a step-down transmission also ineluding a pinion36 engaging a gear 37 which together with a ratchet 41 and a spring-loaded pawl 42 constitutes the overrunning clutch 15'. Ratchet 41 is keyed to a shaft 38 whose extension 16, also shown in FIG. 1,- has a square termination 43 engageable by a socket wrench.

Shaft 38 carries a pinion 39 meshing with'a gear-'40 which is anchored to the outer end of a flat spiral spring representing the force storer 3; the inner end of this spring is'fastened to a shaft 63 whose front portion is threaded and mates with a nut 64 slidably entrained by a set of rods 65 (only two shown) which extend axially from gear 40. Shaft 63, acting as a leadscrew for nut 64, also has keyed to it a gear engaging, via gears 45 and 46, a pinion 47 on a shaft 48 whose front end carries the hub 49 of minute hand 7. A gear train 50, 51, 52, 55

transmits the rotation of shaft at a reduced rate to a sleeve 53 on that shaft which is integral the hub 54 of hour hand 8. A further gear 56 on shaft 48 is in mesh with a pinion 57 on the shaft of a' sprocket wheel 58 whose teeth are alternately engageable, in the wellknown manner, by dogs 59, 60 on a balancing wheel 61 rocking under the control of a hair spring (not shown) whose tension is adjustable by an arm 62.

The front end of nut 64, which represents the follower 10 diagrammatically illustrated in FIG. 1, is beveled and, in an extreme outward position of that nut, engages a pushbutton 67 of switch 68 to break the feedback circuit of multivibrator 1 through conductors 12. Such an interruption of the circuit, occurring when the spring 3 has contracted to a predetermined extent,

prevents further triggering of transistor T so that the pulse generator T T is disabled. It will be apparent that switch 68 could also be inserted elsewhere in the circuit, e. g., in the positive lead of battery Z ahead of its junction resistor R in which case even the small leakage current through resistors R R would be stopped when the spring 3 is fully wound.

The system of FIG. 3 differs from that of FIG. 2 only by the omission of switching circuit 12, 68 which has been replaced by a mechanical device 13(also diagrammatically iridicated in FIG. 1) for stopping the swing of arm 23. This device 13 comprisesa lever 70 with an end 69 projecting into the path of nut 64 for downward'camming, against the force of a restoring spring 72, inthe limiting position of the nut; the opposite end 74 of the lever, normally resting against a fixed stop 73, is then raised into the path of a pin 75 projecting transversely from arm 23, this end being beveled at 76 to intercept that pin anywhere along its stroke and to halt the motion of solenoid core 18 whereby coil 17 acts nearly as a pure inductance drawing mainly reactive current. Though the multivibrator 1 will continue to generate periodic pulses, its consump tion of electric energy will be small.

As shown in FIG. 4, the device 13 may be replaced by another form of mechanical inhibitor 14 (see also FIG. 1) designed as a lever arm 174 normally extending below a stepping pawl 127 coacting' with a ratchet wheel 129; the oscillatory system is here shown as a disk 123 swingable on a shaft 119 under the control of a solenoid core 118 and of an associated hair spring 125. The remainder of the assembly is identical with that of FIG. 3 and has not been illustrated. When the nut 64 (FIG. 3) engages the proximal end of the lever, its extremity 174 moves upwardly to lift the pawl 127 into a disengaged position in which-it cannot step the ratchet 129. In view of the resonance between this oscillatory system and the multivibrator, power consumption is again minimized under these conditions.

Other mechanical inhibitors operating on the same general principle include; for example, a permanent bar magnet carried on the arm 74 of lever 70 (FIG. 3)

to repel the solenoid core 18 when placed in an aligned position therewith. I

It has been found that a clock according to the inven-- tion can be continuously operated in the presence of illumination of as little as l lux with the use of a solar battery consisting of four selenium cells having each an effective area of about cm If the regenerative effect of the solar battery is temporarily insufficient to balance the energy consumption of the load circuit, the pulses generated by multivibrator 1 will be incapable of advancing the ratchet 29 (or 129) during every cycle but may do so after several cycles by progessively building up the swing of the oscillating armature; when illumination is thereafter intensified, normal stepping will be resumed.

During such normal stepping, the nut 64 is advanced axially outwardly (toward blocking device 67 or 70) as the spring 3 is progressively tightened, thus storing enough energy for the next period of failing illumination. Uninterrupted clock operation, even during long winter nights, is thereby assured.

Deactivation at the source, as described in connection with FIG. 2, will be particularly suitable for clockworks whose drive springs 3 or equivalent force storers are designed to keep the movement running without reloading for long periods (e.g., a month); the switch 68 then advantageously includes some delay means, such as a lost-motion linkage, causing it to reclose the circuit 12 in a position of the nut retracted (i.e., shifted to the left) with reference to the position of circuit opening.

On the other hand, a mechanical stop as shown in FIG. 3 or 4 will be suitable where the spring runs down relatively fast; the modification of FIG. 4 is particularly advantageous with oscillating armatures of large moments of inertia.

Though the follower-controlled deactivating devices shown and described are primarily intended to prevent overload, an analogous construction could be used to cut off the accumulator during periods of prolonged nonuse, i.e., upon relaxation of spring 3 to a predetermined extent, in order to conserve electric energy. Such a system could permit even the use of depletionsensitive power sources, such as nickel-cadmium batteries, though the utilization of a more efficient regenerable current supply (e.g., a selenium-type solar battery) is preferred in any case.

I claim:

. l. A timepiece comprising:

a clockwork provided with time-indicating means;

a mechanical force storer coupled with said clockwork for powering same;

reloading means for said force storer including an electronic pulse generator including an astable multivibrator and a stepping drive periodically energized thereby;

a supply of electric current for said pulse generator;

follower means linked with said force storer for displacement dependent upon the degree of loading thereof;

and blocking means operable by said follower means in a predetermined state of loading of said force storer for deactivating said reloading means.

2. A timepiece as defined in claim 1 wherein said multivibrator comprises two cascaded transistors provided with a feedback path.

3. A timepiece as defined in claim 2 wherein said transistors are of opposite conductivity type.

4. A timepiece as defined in claim 2 wherein said blocking means comprises a circuit breaker inserted in said feedback path.

5. A fimepiece as defined in claim 2 wherein said supply comprises a rechargeable battery connected across said transistors and a capacitor in parallel with said battery.

6. A timepiece as defined in claim 5 wherein said battery consists of photoelectric cells.

. 7. A timepiece as defined in claim 2 wherein said stepping drive comprises electromagnetic coil means in series with one of said transistors and a swingable armature in the field of said coil means.

8. A timepiece as defined in claim 7 wherein said blocking means comprises a mechanical stop interposable in the path of said armature.

9. A timepiece as defined in claim 7 wherein said reloading means includes a rotatable shaft and a one-way coupling between said armature and said shaft.

10. A timepiece as defined in claim 9 wherein said one-way coupling includes a pawl and a ratchet, said blocking means being operable to disengage said pawl from said ratchet.

11. A timepiece as defined in claim 9 wherein said shaft is provided with an extension for manually loading said force storer independently of said reloading means.

12. A timepiece as defined in claim 7 wherein said armature comprises a spring-loaded member.

13. A timepiece as defined in claim 1 wherein said force storer comprises a windable coil spring and a leadscrew connected with one end of said coil spring, said follower means being a nut on said leadscrew entrained by the other end of said coil spring for axial displacement along said leadscrew.

14. A timepiece as defined in claim 13 wherein said blocking means comprises an element trippable by said nut in a predetermined axial position thereof.

15. A timepiece as defined in claim 14 wherein said element is an electric switch.

16. A timepiece as defined in claim 14 wherein said element is a lever.

17. A timepiece as defined in claim 1 wherein said follower means is operative to deactivate said reloading means in a position of maximum loading of said force storer.

18. A timepiece comprising:

a clockwork provided with time-indicating means;

a mechanical force storer coupled with said clockwork for powering same, said force storer comprising a windable coil spring, a leadscrew connected to one end of said coil spring, and a nut on said leadscrew entrained by the other end of said coil spring for axial displacement along said leadscrew;

reloading means for said force storer including an electronic pulse generator and a stepping drive periodically energized thereby;

a supply of electric current for said pulse generator;

and blocking means operable by said nut in a predetermined state of loading of said coil spring for deactivating said reloading means.

19. A timepiece as defined in claim 18 whereinsaid blocking means comprises an element trippable by said nut in a predetermined axial position thereof.

20. A timepiece as defined in claim 19 wherein said element is an electric switch.

21. A timepiece as defined in claim 19 whel ein said element is a lever.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3474618 *Apr 28, 1967Oct 28, 1969Hamilton Watch CoRewind mechanism for an electric timepeace
DE1045917B *Apr 3, 1956Dec 4, 1958Kieninger & ObergfellVon einer Gleichstromquelle gespeiste elektrische Selbstaufzugsuhr
IT442667A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4782276 *Apr 7, 1987Nov 1, 1988SolemsElectric signal generator system and its application
US4901295 *Dec 9, 1988Feb 13, 1990Asulab S.A.Device comprising a solar cell for winding a barrel spring
US5760572 *May 9, 1997Jun 2, 1998Tagawasyouji Co., Ltd.Intermittent motion apparatus
US6462444Jul 26, 2000Oct 8, 2002Panpop MakkunPower apparatus with low energy consumption
US7626892 *May 1, 2006Dec 1, 2009Tai-Her YangTiming device with power winder
US9019802 *Nov 29, 2012Apr 28, 2015Seiko Epson CorporationSolar-powered electronic timepiece
US20070252434 *May 1, 2006Nov 1, 2007Tai-Her YangHybrid power timing device
US20130142018 *Nov 29, 2012Jun 6, 2013Seiko Epson CorporationElectronic timepiece
EP0685924A3 *May 31, 1995Nov 27, 1996Ueda Co LtdSolar cell system and intermittent motion apparatus using same.
EP1072769A2 *Jul 28, 2000Jan 31, 2001Panpop MakkunPower apparatus with low energy consumption
EP1072769A3 *Jul 28, 2000Mar 6, 2002Panpop MakkunPower apparatus with low energy consumption
EP1988434A1 *Apr 30, 2007Nov 5, 2008Tai-Her YangHybrid power timing device
WO2011092405A1 *Jan 28, 2011Aug 4, 2011Regantox SaMechanical watch with automatic windup and method for automatically winding up such a watch
Classifications
U.S. Classification368/149, 368/205, 368/207, 968/504, 968/429, 368/80
International ClassificationG04C10/02, G04C1/00, G04C10/00, G04C1/02
Cooperative ClassificationG04C10/02, G04C1/067
European ClassificationG04C10/02, G04C1/06D