US 3005305 A
Description (OCR text may contain errors)
F. THOMA ELECTRIC WATCH} Oct. 24, 1961 2 Sheets-Sheet 2 Filed Jan. 6, 1958 Fig. 8
United States Patent 3,005,305 7 ELECTRIC WATCH Fritz Thoma, .St. Georgen, Black Forest, Germany, as-
signor =to Kieninger & Obergfell, St. Georgen, Black Forest, Germany Filed Jan. 6, 1958, 'Ser. No. 707,440 Claims priority, application Germany Jan. 4,, 1957 '4 Claims. ((31. 58-48) This invention relates to electric watches and the like, and its particular object is to improve the control means of a battery-operated electric watch, frequency standard, time standard, and other small appliances, so as to obtain long life for the battery.
It is known to provide a battery-operated watch with a "photocell adapted responsive to illumination to charge the battery or to provide a casing for a watch permitting charging of the battery from time to time from an extraneous current source. These expedients are, however, not entirely reliable. The photocell, if used, is frequently covered up by wearing apparel, especially in the case of men's wrist watches and illumination with an intensity for supplying sufficient energy is accordingly uncertain. The charging of the battery from time to time, from a commercial or other extraneous current source might be inadvertently omitted, thus causing destructive loading of the battery due to excessive discharge thereof.
The object of theinvention isto improve the electrical circuit of the entire clock so as to increase the life of the battery automatically; this object has not been posed in the past. The invention is in this connection directed to the use, in connection with watches and the like, of chargeable batteries, accumulators or chargeable primary elements, as well as non-chargeable primary elements.
The invention, accordingly, provides two diiferentmeasures, one being mainly concerned with non-chargeable primary elements and theother mainly with accumulators. Both measures are individually or in combination applicable to chargeable primaryelements.
The thoughts and investigations underlying the invention have revealed, first, that it is in connection with the corresponding circuit arrangements possible to operate with electric currents in part on the order of less than 1 ma., and second, that a highgrade battery and especially a primary element is not saved step-by-step or best preserved and given increased life by stepwise reduced current loading, but that :there is an optimum small current loading for-the best preservation thereof.
The invention solves the problems posed by'match'ing the electronic circuit arrangement to the optimum discharge current strength of the primary element employed at which is obtained the most accurate and longest lasting constancy of the battery voltage. For this purpose, the mechanical and electrical members of the electronic control arrangement must be dimensioned soas to operate, for long life, on the one hand under the maximum current strength and, 'on the other hand, at a minimum current strength, resulting'within a few days of current how in a linear voltage course for a time as long as possible.
in accordancewith a particular embodiment of the invention, the minimum 'currentstrength is to be of a magnitudesuch that no active hydrogen is .formed on the oathode. The type o'f'battery provided for a small electricappliance or device, especially an electric watch with transistor control, is loaded with stepwise diminishing current strengths until-active hydrogen starts to form on the cat. ode. The current strength lying just above the magnitude at which no active hydrogen is formed on the cathode serves as a criterion for the dimensioning of the electrical circuit.
It is, for example, in most cases desirable to provide for a battery load lying under about 0.3 ma., preferably a value between about 0.03 ma. and 0.09 ma., for example, about 0.07 ma.
The part of the invention relating to chargeable batteries, especially to accumulators, contemplates the useof a charging current source made in the form of a current generator actuated by relative motion between at least two 'of its parts.
A particularly advantageous embodiment of the invention combines the battery or accumulator cooperatively with a pendulum-like mass which is activated automatically by forces acting upon the watch casing, for example, by shocks resulting from bodily motions of the arm, in a similar manner as known from automatic mechanical watches, such mass cooperating electrodynamically with an induction coil device .adapted to deliver electrical energy for the charging of the battery. The swinging mass is suitably made in the form of a permanent magnet, for example, a ferrite rod or body; the coil arrangement may be connected with the terminals of the battery by way of a rectifier or a two-way rectifier.
The foregoing and further objects and features of the invention 'will appear from the description of embodiments which will be rendered below with reference to the accompanying drawings. In the drawings,
FIGS. 1 to 3 are curves illustrating the discharge course of an air-oxygen element;
'FIGS. 4 and 5 show an electronic control arrangement for a balance watch comprising a primary element;
FIG. 6 shows some details;
FIG. 7 indicates a device for charging the battery shown in FIG. 5; and i 7 FIG. 8 is a schematic circuit for the charger according to FIG. 7.
On the abscissa in 'FIGS. '1 to '3,showing curves for the discharge course of a battery, for example, an air-oxygen element, are plotted the years and along the ordinate the corresponding terminal voltages in volts. FIG. 1 shows-the conditions incident, to steady battery load on the order of about 1 ma. FIG. 2 shows the conditions in case of an unloaded battery which is in storage. The curve according to FIG. 3 results in steady loading of the battery at about 0.3 ma. It will be seen from the curves that .a favorable uniform low discharge current strength of the battery results not only in considerably greater constancy of the battery voltage but also in considerably longer battery life. The values to the right of the vertical line 1 are in part based upon measurements :and in part upon information'received from battery manufacturers concern ing estimatedstorage time properties; the constancy of the curve branches at the left of line 1 clearly illustrates the good constancy of the battery voltage resulting from op.- eration in accordance with the rule .of the invention. The optimum discharge current strength is around 0.07 ma.
"For the optimum design of the electronic control (for a watch with feedback circuit, using a' semiconductor structural element, especially transistor, wherein an electrically driven mechanical oscillator cooperates with a generator coil and a motor coil, the mechanical oscillator is according to a particular embodiment of the invention made in the form of a pure frequency standard and relay means is provided for the drive of the pointers which are governed by the electronic control. The relay coil is suitably disposed in parallel with the motor coil in the output circuit of the semiconductor, preferably transistor circuit and/or amplifier means. The controlling semiconductor element is suitably made to operate for the pointer drive is to be dimensioned so as to replace wholly or in part the resistor for the electrical compensation and particularly for the suppression of hunting of the transistor, so that such resistor may be omitted.
FIGS. 4 and 5 show an electronic control for a 'balance watch to give an example. Numeral 2 indicates a rodlike permanent magnet disposed upon the balance wheel 11 and adapted to oscillate in the plane of the drawing opposite to the directional force of the spiral balance spring 3. Numeral 12 indicates a magnetic return flux plate. The oscillations are maintained in previously proposed manner by two coils 4 and 5, one wound upon the other, which are connected in feedback circuit byway of a transistor 6. Battery 7 serves as a source for the energy. Parallel to the motor coil 5, in the output circut, that is, in the illustrated example, in the emitter-collector circuit of the transistor, there is disposed a polarized relay 8. The winding of relay 8 is so dimensioned that it also serves as a compensation resistance for stabilizing the transistor circuit. The relay 8 has an armature 9 for advancing a rotatable element or gear wheel 10 incident to each change of polarity, the gear wheel 10 being suitably connected with a pointer drive. The oscillator 2 produces incident to each forth and back motion a single impulse in the generator coil 4. All data for the electronic circuit are such that a current on the order of an average of about 0.07 ma. will fiow in the emitter-collector circuit. The transistor must have a characteristic that extends in the neighborhood of the working point substantially horizontally so that the transistor operates purely as a switch without effecting amplification. A particularly steep impulse, contributing favorably to the operation, may be obtained by particular configuration of the magnet, for example, in the shape of a horseshoe magnet.
The battery 7 in FIG. 5 may be charged by a charging device schematically illustrated in FIG. 7.
The invention is not inherently limited to the illustrated example. It is within the scope of the invention to use, depending upon the purpose thereof, an oscillator other than a balance, for example a pendulum, or to dispose the magnet in fixed position and make the coil arrangement in the form of a movable oscillator. In order to effect discharge of the battery as uniform as possible, smoothing means, especially capacitor means may be provided ahead thereof, for smoothing the impulse-like discharge and thus effecting continuous loading of the battery. As already initially mentioned, another induction means, for example, structural elements operating without contacts may be substituted for the coils 4 and 5, and corresponding different switching means may take the place of the transistor.
FIG. 6 illustrates a drive for directly deriving from the oscillating motions of the balance 11 (FIGS. 4 and 5) a stepwise motion without the use of the relay ti and drive means 9 and 10. in this case, the balance drives a ratchet which in turn rotates under control of a detent, to drive the watch pointers.
In FIG. 7, numeral 13 indicates the casing of a wrist watch comprising a pendulum body 14 which is rotatable about axis 15, the principal part of the pendulum body being formed by a segment-like permanent magnet N-S. Two induction coils l6 and 17 are provided in which are induced electrical current and voltage impulses, by the motions of the magnetic poles N-S, such impulses serving for the charging of a battery such as the battery 7 in FIG. 5. If desired, further coils 18 and 19 may be provided, as indicated in dash lines. The oscillating mass 14 may execute an oscillating motion between resilient stops, analogous to the motion of masses provided in mechanical watches for winding the mainspring,
or may be rotatable through 360 in both directions of rotation. The battery to be charged by the charger according to FIG. 7 is assumed to be the battery 7 shown in FIG. 5.
FIGS shows in schematic manner a circuit scheme for effecting the charging of the battery. Numeral 7 indicates the battery with its terminals 20 and 21 which are connected with the watch, the coils 16 and 17 being cooperable with the mass 14 oscillating in the directions of the curved arrow. Numeral 22 indicates a rectifier in the circuit of the coil means to the terminals of the battery 7'. The battery is, of course, placed in the control circuit of the watch in a manner analogous to the battery shown in FIG. 5.
Changes may be made within the scope and spirit of the appended claims.
1. In an electric watch or the like having an electronic drive control comprising a magnetic oscillator driven by a circuit including a battery, a transistor and a pair of induction coils, one of which is operatively connected to the transistor input, and the other coil and said battery to the transistor output, a polarized relay operatively connected to the transistor output with said battery and induction coil, and means controlled by said relay for driving a rotatable element of the watch, the resistance of said relay being operative to stabilize the operation of said transistor, the latter being arranged to operate as a switch without amplification, with the operating current of said battery being at a minimum value in linear voltage course for the maximum operating time.
2. A structure according to claim 1, in combination with a device for charging said battery consisting of a segment-shaped mass including permanent magnet means which mass is rotatably disposed in said watch and automatically angularly moved responsive to movement imparted to the watch, and further induction coil means operatively connected to said battery and disposed in the casing of said watch marginally thereof for cooperation with the permanent magnet means of said mass for producing responsive to angular motion of said mass electric energy for charging said battery.
3. A structure according to claim 2, wherein said further induction coil means comprises at least two induction coils angularly spaced from each other by a distance corresponding to the angular spacing between the poles of the permanent magnet means carried by said mass.
4. A structure according to claim 2, wherein said segment-shaped mass is rotatably mounted in the watch at a point coinciding with the axis of said Watch for free rotation about such axis, and rectifying means connected in series with said coil and battery for the passage of induced current only in a battery-charging direction.
References Cited in the file of this patent UNITED STATES PATENTS 1,175,610 Cove Mar. 14, 1916 2,791,732 Jones May 7, 1957 2,807,133 Maire Sept. 24, 1957 2,829,824 Sargeant Apr. 1, 1958 2,843,742 Cluwen July 15, 1958 FOREIGN PATENTS 1,090,564 France Oct. 20, 1954 746,465 Great Britain Mar. 14, 1956 OTHER REFERENCES Favarger, A.: LElectricite et ces application a la Chronornetric, 3e edition, Neuchatel 1924, p. 305, Figure 210.