US3803829A - Coil structure for electric watches - Google Patents

Coil structure for electric watches Download PDF

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US3803829A
US3803829A US00336298A US33629873A US3803829A US 3803829 A US3803829 A US 3803829A US 00336298 A US00336298 A US 00336298A US 33629873 A US33629873 A US 33629873A US 3803829 A US3803829 A US 3803829A
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driving
coil
detecting
permanent magnets
balance wheel
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US00336298A
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Y Tsuruishi
M Matsuzawa
O Naito
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Suwa Seikosha KK
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Suwa Seikosha KK
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    • G—PHYSICS
    • G04—HOROLOGY
    • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C3/00—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means
    • G04C3/04—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance
    • G04C3/06—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance using electromagnetic coupling between electric power source and balance
    • G04C3/065—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance using electromagnetic coupling between electric power source and balance the balance controlling gear-train by means of static switches, e.g. transistor circuits
    • G04C3/067—Driving circuits with distinct detecting and driving coils
    • G04C3/068—Driving circuits with distinct detecting and driving coils provided with automatic control
    • G—PHYSICS
    • G04—HOROLOGY
    • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C3/00—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means
    • G04C3/04—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance
    • G04C3/06—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance using electromagnetic coupling between electric power source and balance
    • G04C3/065—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance using electromagnetic coupling between electric power source and balance the balance controlling gear-train by means of static switches, e.g. transistor circuits
    • G04C3/067—Driving circuits with distinct detecting and driving coils

Definitions

  • ABSTRACT A coil structure for an electric watch having a balance wheel formed with a pair of spaced discs on which are mounted two pairs of permanent magnets aligned in facing relation on said discs. Detecting and driving coils are wound coaxially and mounted separate from said balance wheel in the gap between said permanent magnets. The detecting and driving coils are mounted so that, at the center of oscillation of the balance wheel, most of the magnetic flux is interlinked with a respective side of the driving coil.
  • the present invention relates to a coil form of electric watch with permanent magnets mounted on the balance wheel.
  • the object of this invention is to improve the coil of such electric watches with permanent magnets mounted on the balance wheel and to provide a low-priced electric watch.
  • the magnetic flux density of the permanent magnet is increased and turns on the coil are increased in order to obtain a wide amplitude of oscillation of the balance wheel through a small consumption current.
  • an electric watch having an oscillating balance wheel carrying two pairs of permanent magnets defining a magnetic circuit having air gaps between facing permanent magnets of opposite polarity.
  • Fixed detecting and driving coils are provided wound coaxially and mounted in the gaps between the permanent magnets.
  • Driving circuit means is provided including the driving and detecting coils, the driving circuit means being adapted to apply driving pulses to the driving coils in response to each pulse induced in the detecting coil of a selected polarity.
  • the object of this invention is to provide magnet and coil of compact size which would permit a low manufacturing cost by eliminating the above disadvantages, i.e. to provide a method which increases driving efficiency of a coil wound with thick wire and having a relatively small number of turns. it is thus possible to obtain a highly efficient electric watch using a low-priced magnet and coil.
  • FIG. 1 is a front view of a balance wheel and the coils of the conventional type of electric watch with permanent magnets mounted on the balance wheel;
  • FIG. 2 is a plane view of the balance wheel and the coils of FIG. 1:
  • FIG. 3 shows one embodiment of a driving circuit of the conventional type of electric watch with permanent magnets mounted on the balance wheel
  • FIG. 4 shows voltage wave forms at three points in the driving circuit of the conventional type of electric watch with permanent magnets mounted on the balance wheel shown in FIG. 3;
  • FIG. 5 is a front view of the balance wheel and the coils of the electric watch with permanent magnets mounted on the balance wheel according to the invention
  • FIG. 6 shows one embodiment of the coil according to the invention
  • FIG. 7 shows voltage wave forms at said three points in said driving circuit of the electric watch with permanent magnets mounted on the balance wheel according to the invention
  • FIG. 8 is a top plan view of the balance wheel and coils of FIG. 5;
  • FIGS. 9(a), 9(b) and 9(c) are schematic front views of the balance wheel and coils in accordance with the invention depicted respectively at three relative positions;
  • FIG. 10 shows wave forms of the voltage induced in the detecting and driving coils respectively.
  • FIG. I is a front view of the balance wheelof a conventional type of electric watch with permanent magnets mounted on the balance wheel provided with two discs, and wherein Z is a balance staff and 3, 4i, 5 and 6 are permanent magnets. Permanent magnets 3 and 5 are disposed in alignment with and facing permanent magnets 4 and 6 respectively. 7 is a phase detecting coil and 8 is the driving coil.
  • FIG. 2 is a plan view of FIG. 1 wherein 9 is a winding frame, 10 and 1111 are balancing weights for balancing the balance wheel, 12 corresponds to the permanent magnets 3 and 4, 13 corresponds to the permanent magnets 5 and 6, and M is a coil.
  • the coil is formed with a detecting coil 7 and a driving coil 3.
  • the detecting coil and the driving coil can be formed as a unit by winding the two coils together.
  • FIG. 3 shows one embodiment of the driving circuit of the electric watch with permanent magnets mounted on the balance wheel.
  • 15 is a detecting coil, 16 a condenser for cutting off the direct current.
  • 17 a base bias resistance, W the driving coil, 19 a driving transistor and 20 a voltage source of direct current.
  • FIG. 4 shows voltage wave forms at points A, B, C of said driving circuit when driving the balance wheel of FIG. 1.
  • a wave form of the voltage induced in the detecting coil 15 is shown by a broken line in FIG. 4(A).
  • the wave form at operating times falls down in a range where the driving transistor is conducting as shown by the wave form in solid line, due to the addition of the voltage drop of internal resistance caused by the electric current flowing in detecting coil 15.
  • An induced voltage having a phase opposite to that of detecting coil 15 occurs on the collector side of driving coil 18 as shown in FIG. 4.
  • the condenser 16 for cutting off the direct current is charged by the current flowing from the detecting coil to the base.
  • the charging voltage is used as a base bias voltage for keeping the driving transistor in cut off condition when the driving transistor is cut off. This is apparent from FIG. 4(B).
  • the peak value of the positive side of the detecting voltage caused by oscillation of the balance wheel is not the same where the balance wheel moves clockwise or counterclockwise. The same is true in the case of the current flowing in the base.
  • the difference in the base bias voltage between immediately before a single driving pulse occurs and a double driving pulse occurs is V If the base bias resistance is too small, the driving transistor enters into the conducting area before the single driving pulse occurs, and unnecessary current consumption is increased. If the base bias resistance is too large, the negative base bias voltage is increased and the width of the driving pulse and the amplitude are reduced. The base bias resistance must fall within a proper range of values for securing the operation of the balance wheel and it is necessary that the double detecting voltage be large enough in the above range of values.
  • the driving transistor cannot conduct perfectly unless enough detecting voltage is produced, the internal loss of the transistor is increased, and the amplitude of the balance wheel is reduced.
  • turns on the detecting coil should be added in order to obtain enough detecting voltage.
  • turns on the driving coil should be reduced to contain the coil in a limited area.
  • the voltage induced in the driving coil is reduced, the increased current consumption is not applied as energy for the balance wheel and the amplitude is reduced.
  • many more turns of very thin wire are added on conventional coil structures.
  • FIG. is a front view of the balance wheel of one embodiment of an electric watch with magnets mounted on the balance wheel according to the invention.
  • 21 is a driving coil and 22 a detecting coil.
  • FIG. 6 is a plan view of the coils 21 and 22.
  • 23 is an inner terminal, 24 a connecting point between the driving coil 21 and the detecting coil 22, 25 an outer terminal and 26 a coil frame.
  • FIG. 7 shows the voltage wave forms at three points in the circuit of FIG. 3 when the wires of the detecting and driving coils are wound coaxially.
  • FIG. 7 corresponds to FIG. 4. If the wires of the coils are wound coaxially, the magnetic flux produced by pairs of magnets, 3, 4 and 5, 6 does not pass through the detecting coil 22 at the same time, so the peak values on positive and negative sides of the induced voltage in the detecting coil 22 are the same as shown in FIG. 7. Base bias voltage is almost the same immediately before the single and double driving pulses occur as shown in FIG. 7(3). The difference V, of FIG. 7 is much smaller than V,,, in FIG. 4(B).
  • the driving transistor can be conductive as the negative base bias voltage is reduced, and turns on the detecting coil 22 may be reduced.
  • low-priced thick wire can be used.
  • the phase of the driving current is a little shifted from a phase at which the driving current gives maximum energy to the magnet, but actually this makes no difference.
  • the connecting point 24 is connected to an electric source, an advantageous arrangement for disposing the terminals of coils.
  • FIGS. 8 and 9 it is seen that balance wheel 1 oscillates so that the permanent magnets pass driving coil 21 and detecting coil 22.
  • Double headed arrow 27 of FIG. 8 represents the locus of the path of the center portion of the permanent magnets.
  • FIG. 10(a) depicts a voltage induced in the detecting coil 22 during each cycle of oscillation
  • FIG. 10(b) depicts the voltage induced in the driving coil during each such cycle.'Three points in the forward motion portion of the cycle are identified as 1,, t and I
  • the relative position of the permanent magnets and the driving and detecting coils at each of said three times are depicted respectively in FIGS. 9(a), 9(b) and 9(c).
  • Time t represents the center of oscillation of the balance wheel, at which point it is seen from FIG. 9(c) that most of the magnetic flux of the field passing through each pair of the permanent magnets is interlinked with a respective side of the driving coil. Further, it is apparent that, at said center of oscillation, the magnetic flux interlinked with the detecting coil is substantially smaller than that interlinked with the driving coil. In this matter, maximum driving force is applied to the balance wheel at said center of oscillation, thereby insuring efficient and accurate driving of the balance wheel in both directions of oscillation thereof.
  • turns on the detecting coil of an electric watch with magnets mounted on the balance wheel can be reduced and consequently, as turns on the driving coil can be increased, the coil can be made by using a relatively thick wire.
  • a low-priced coil adapted for easy handling can be obtained.
  • This structure is also very advantageous for mass scale production of this type of electric watch.
  • the detecting voltage may be small according to the invention, lower-priced magnets may be used.
  • An electric watch comprising an oscillating balance wheel having a shaft and a pair of spaced discs mounted on said shaft; two pairs of permanent magnets, one of each of said pairs of permanent magnets being mounted on each of said discs in facing relation to the other of said permanent magnets, the permanent magnets of each of said pairs being polarized to produce a magnetic field in the gap therebetween extending in a direction opposite to the field in the gap between the other of said pairs of permanent magnets so as to form a closed magnetic circuit; a detecting coil; a driving coil, said detecting and driving coils being separate from said balance wheel and mounted in the gaps between said permanent magnets, said detecting coil being wound coaxially inside of said driving coil, said detecting and driving coils being positioned so that, at the center of oscillation of said balance wheel most of the magnetic flux of said field passing through each pair of said permanent magnets is interlinked with a respective side of said driving coil, and so that, at said center of oscillation, the magnetic flux interlinked with said detecting coil is substantially smaller than that interlinked
  • said driving circuit means includes transistor means having a base, emitter and collector; a voltage source, said driving coil and voltage source being connected in series with the emitter-collector path of said transistor means; and base circuit means including said detecting coil, capacitor means connected in series with said detecting coil and resistor means connected in parallel with said series connection of said detecting coil and capacitor means, the time constant of said capacitor means and resistor means being selected such that said transistor means is driven to conduction to apply a driving pulse to said driving coil in response to each of said pulses induced in said detecting coil of a selectedpolarity.

Abstract

A coil structure for an electric watch having a balance wheel formed with a pair of spaced discs on which are mounted two pairs of permanent magnets aligned in facing relation on said discs. Detecting and driving coils are wound coaxially and mounted separate from said balance wheel in the gap between said permanent magnets. The detecting and driving coils are mounted so that, at the center of oscillation of the balance wheel, most of the magnetic flux is interlinked with a respective side of the driving coil.

Description

United States Patent 1191 Tsuruishi et a1.
COIL STRUCTURE FOR ELECTRIC WATCHES Inventors: Yuki Tsuruishi; Okito Naito;
Masanao Matsuzawa, all of Suwa, Japan Assignee: Kabushiki Kaisha Suwa Seikosha,
Tokyo, Japan Filed: Feb. 27, 1973 Appl. No.: 336,298
Related U.S. Application Data Continuation-impart of Ser. No. 127,893, March 25, 1971, abandoned.
Foreign Application Priority Data Mar. 31, 1970 Japan 45-26529 U.S. Cl 58/28 A, 310/36, 318/132 lint. Cl .L G04c 3/04 Field of Search 58/28 R, 28 A; 310/36;
[ Apr. 16, 1974 [561 References Cited UNITED STATES PATENTS 3,365,635 1/1968 Shelley 318/128 3.s1s,s1s 6/1970 Reich 318/128 3,524,118 8/1970 Reich 318/128 Primary Examiner-Lawrence R. Franklin Attorney, Agent, or Firm--Blum, Moscovitz, Friedman & Kaplan [5 7] ABSTRACT A coil structure for an electric watch having a balance wheel formed with a pair of spaced discs on which are mounted two pairs of permanent magnets aligned in facing relation on said discs. Detecting and driving coils are wound coaxially and mounted separate from said balance wheel in the gap between said permanent magnets. The detecting and driving coils are mounted so that, at the center of oscillation of the balance wheel, most of the magnetic flux is interlinked with a respective side of the driving coil.
2 Claims, 12 Drawing Figures PATENTEDAPR 1 6 1974 SHEET 0F Q COIL STRUCTURE FOR ELECTRIC WATCHES This is a continuation-in-part of our co-pending application Ser. No. 127,893 filed Mar. 25, 1971 now abandoned.
BACKGROUND OF THE INVENTION The present invention relates to a coil form of electric watch with permanent magnets mounted on the balance wheel. The object of this invention is to improve the coil of such electric watches with permanent magnets mounted on the balance wheel and to provide a low-priced electric watch. In an electric watch with permanent magnets mounted on the balance wheel, wherein the balance wheel is provided with permanent magnets and driven by a coil mounted outside thereof, the magnetic flux density of the permanent magnet is increased and turns on the coil are increased in order to obtain a wide amplitude of oscillation of the balance wheel through a small consumption current.
In such prior art arrangements, a highly effective magnetic material such as platinum cobalt was used as a permanent magnet and a very thin wire was wound closely on the coil in order to make the parts smaller about the balance. Such permanent magnets and coil wire were of high cost, while the making and handling of the coil at assembly proved difficult.
In order to eliminate the above disadvantages, it was proposed that when a low-priced permanent magnet is used, the shape of magnet should be large in order to obtain the necessary magnetic flux density or a very thin wire should be wound closely on the coil in order that the watch can be operated even if the magnetic flux density is small. However, neither of these alternatives are desirable for the efficiency of the watch and the production thereof.
SUMMARY OF THE INVENTION Generally speaking, in accordance with the invention, an electric watch is provided having an oscillating balance wheel carrying two pairs of permanent magnets defining a magnetic circuit having air gaps between facing permanent magnets of opposite polarity. Fixed detecting and driving coils are provided wound coaxially and mounted in the gaps between the permanent magnets. The detecting and driving coils'are positioned so that, at the center of oscillation of the balance wheel, most of the magnetic flux of the field passing through each pair of the permanent magnets is inter linked with a respective side of the driving coil, and so that, at said center of oscillation, the magnetic flux interlinked with the detecting coil is substantially smaller than that interlinked with the driving coil. Driving circuit means is provided including the driving and detecting coils, the driving circuit means being adapted to apply driving pulses to the driving coils in response to each pulse induced in the detecting coil of a selected polarity. I
The object of this invention is to provide magnet and coil of compact size which would permit a low manufacturing cost by eliminating the above disadvantages, i.e. to provide a method which increases driving efficiency ofa coil wound with thick wire and having a relatively small number of turns. it is thus possible to obtain a highly efficient electric watch using a low-priced magnet and coil.
BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:
FIG. 1 is a front view of a balance wheel and the coils of the conventional type of electric watch with permanent magnets mounted on the balance wheel;
FIG. 2 is a plane view of the balance wheel and the coils of FIG. 1:
FIG. 3 shows one embodiment of a driving circuit of the conventional type of electric watch with permanent magnets mounted on the balance wheel;
FIG. 4 shows voltage wave forms at three points in the driving circuit of the conventional type of electric watch with permanent magnets mounted on the balance wheel shown in FIG. 3;
FIG. 5 is a front view of the balance wheel and the coils of the electric watch with permanent magnets mounted on the balance wheel according to the invention;
FIG. 6 shows one embodiment of the coil according to the invention;
FIG. 7 shows voltage wave forms at said three points in said driving circuit of the electric watch with permanent magnets mounted on the balance wheel according to the invention;
FIG. 8 is a top plan view of the balance wheel and coils of FIG. 5;
FIGS. 9(a), 9(b) and 9(c) are schematic front views of the balance wheel and coils in accordance with the invention depicted respectively at three relative positions; and
FIG. 10 shows wave forms of the voltage induced in the detecting and driving coils respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference is made to the drawings wherein FIG. I is a front view of the balance wheelof a conventional type of electric watch with permanent magnets mounted on the balance wheel provided with two discs, and wherein Z is a balance staff and 3, 4i, 5 and 6 are permanent magnets. Permanent magnets 3 and 5 are disposed in alignment with and facing permanent magnets 4 and 6 respectively. 7 is a phase detecting coil and 8 is the driving coil.
FIG. 2 is a plan view of FIG. 1 wherein 9 is a winding frame, 10 and 1111 are balancing weights for balancing the balance wheel, 12 corresponds to the permanent magnets 3 and 4, 13 corresponds to the permanent magnets 5 and 6, and M is a coil.
In FIG. l, the coil is formed with a detecting coil 7 and a driving coil 3. The detecting coil and the driving coil can be formed as a unit by winding the two coils together.
FIG. 3 shows one embodiment of the driving circuit of the electric watch with permanent magnets mounted on the balance wheel. In FIG. 3, 15 is a detecting coil, 16 a condenser for cutting off the direct current. 17 a base bias resistance, W the driving coil, 19 a driving transistor and 20 a voltage source of direct current.
FIG. 4 shows voltage wave forms at points A, B, C of said driving circuit when driving the balance wheel of FIG. 1. A wave form of the voltage induced in the detecting coil 15 is shown by a broken line in FIG. 4(A). The wave form at operating times falls down in a range where the driving transistor is conducting as shown by the wave form in solid line, due to the addition of the voltage drop of internal resistance caused by the electric current flowing in detecting coil 15. An induced voltage having a phase opposite to that of detecting coil 15 occurs on the collector side of driving coil 18 as shown in FIG. 4. When the base voltage B rises above the base conducting level of the driving transistor, the electric current flows in the base through detecting coil 15 and the collector voltage C of the driving transistor goes down'to the conductive level.
At this moment, the condenser 16 for cutting off the direct current is charged by the current flowing from the detecting coil to the base. The charging voltage is used as a base bias voltage for keeping the driving transistor in cut off condition when the driving transistor is cut off. This is apparent from FIG. 4(B). The peak value of the positive side of the detecting voltage caused by oscillation of the balance wheel is not the same where the balance wheel moves clockwise or counterclockwise. The same is true in the case of the current flowing in the base.
Therefore, the difference in the base bias voltage between immediately before a single driving pulse occurs and a double driving pulse occurs is V If the base bias resistance is too small, the driving transistor enters into the conducting area before the single driving pulse occurs, and unnecessary current consumption is increased. If the base bias resistance is too large, the negative base bias voltage is increased and the width of the driving pulse and the amplitude are reduced. The base bias resistance must fall within a proper range of values for securing the operation of the balance wheel and it is necessary that the double detecting voltage be large enough in the above range of values.
Because the negative bias voltage, which occurs immediately before the double detecting voltage, is much increased, the driving transistor cannot conduct perfectly unless enough detecting voltage is produced, the internal loss of the transistor is increased, and the amplitude of the balance wheel is reduced.
As is clear from above, turns on the detecting coil should be added in order to obtain enough detecting voltage. llowever, turns on the driving coil should be reduced to contain the coil in a limited area. As a result, the voltage induced in the driving coil is reduced, the increased current consumption is not applied as energy for the balance wheel and the amplitude is reduced. In order to avoid above disadvantages, many more turns of very thin wire are added on conventional coil structures.
The object of this invention is to provide a method wherein turns on the detecting coil are reduced. FIG. is a front view of the balance wheel of one embodiment of an electric watch with magnets mounted on the balance wheel according to the invention. In FIG. 5, 21 is a driving coil and 22 a detecting coil.
FIG. 6 is a plan view of the coils 21 and 22. 23 is an inner terminal, 24 a connecting point between the driving coil 21 and the detecting coil 22, 25 an outer terminal and 26 a coil frame.
FIG. 7 shows the voltage wave forms at three points in the circuit of FIG. 3 when the wires of the detecting and driving coils are wound coaxially. FIG. 7 corresponds to FIG. 4. If the wires of the coils are wound coaxially, the magnetic flux produced by pairs of magnets, 3, 4 and 5, 6 does not pass through the detecting coil 22 at the same time, so the peak values on positive and negative sides of the induced voltage in the detecting coil 22 are the same as shown in FIG. 7. Base bias voltage is almost the same immediately before the single and double driving pulses occur as shown in FIG. 7(3). The difference V, of FIG. 7 is much smaller than V,,, in FIG. 4(B).
Therefore, even if the peak value of double detecting voltage is small, the driving transistor can be conductive as the negative base bias voltage is reduced, and turns on the detecting coil 22 may be reduced. Thus, low-priced thick wire can be used. The phase of the driving current is a little shifted from a phase at which the driving current gives maximum energy to the magnet, but actually this makes no difference. In the coil according to this invention, the connecting point 24 is connected to an electric source, an advantageous arrangement for disposing the terminals of coils.
Referring now to FIGS. 8 and 9, it is seen that balance wheel 1 oscillates so that the permanent magnets pass driving coil 21 and detecting coil 22. Double headed arrow 27 of FIG. 8 represents the locus of the path of the center portion of the permanent magnets. FIG. 10(a) depicts a voltage induced in the detecting coil 22 during each cycle of oscillation, while FIG. 10(b) depicts the voltage induced in the driving coil during each such cycle.'Three points in the forward motion portion of the cycle are identified as 1,, t and I The relative position of the permanent magnets and the driving and detecting coils at each of said three times are depicted respectively in FIGS. 9(a), 9(b) and 9(c). Time t;, represents the center of oscillation of the balance wheel, at which point it is seen from FIG. 9(c) that most of the magnetic flux of the field passing through each pair of the permanent magnets is interlinked with a respective side of the driving coil. Further, it is apparent that, at said center of oscillation, the magnetic flux interlinked with the detecting coil is substantially smaller than that interlinked with the driving coil. In this matter, maximum driving force is applied to the balance wheel at said center of oscillation, thereby insuring efficient and accurate driving of the balance wheel in both directions of oscillation thereof.
As described above, according to the invention, turns on the detecting coil of an electric watch with magnets mounted on the balance wheel can be reduced and consequently, as turns on the driving coil can be increased, the coil can be made by using a relatively thick wire. As a result, a low-priced coil adapted for easy handling can be obtained. This structure is also very advantageous for mass scale production of this type of electric watch. Moreover, as the detecting voltage may be small according to the invention, lower-priced magnets may be used.
It will thus be seen that the objects set forth above, and those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
What is claimed is:
1. An electric watch comprising an oscillating balance wheel having a shaft and a pair of spaced discs mounted on said shaft; two pairs of permanent magnets, one of each of said pairs of permanent magnets being mounted on each of said discs in facing relation to the other of said permanent magnets, the permanent magnets of each of said pairs being polarized to produce a magnetic field in the gap therebetween extending in a direction opposite to the field in the gap between the other of said pairs of permanent magnets so as to form a closed magnetic circuit; a detecting coil; a driving coil, said detecting and driving coils being separate from said balance wheel and mounted in the gaps between said permanent magnets, said detecting coil being wound coaxially inside of said driving coil, said detecting and driving coils being positioned so that, at the center of oscillation of said balance wheel most of the magnetic flux of said field passing through each pair of said permanent magnets is interlinked with a respective side of said driving coil, and so that, at said center of oscillation, the magnetic flux interlinked with said detecting coil is substantially smaller than that interlinked with said driving coil; and driving circuit means including said driving and detecting coils, said driving circuit means being adapted to apply driving pulses to said driving coils in response to each pulse induced in said detecting coil of a selected polarity.
2. An electric watch as recited in claim 2, wherein said driving circuit means includes transistor means having a base, emitter and collector; a voltage source, said driving coil and voltage source being connected in series with the emitter-collector path of said transistor means; and base circuit means including said detecting coil, capacitor means connected in series with said detecting coil and resistor means connected in parallel with said series connection of said detecting coil and capacitor means, the time constant of said capacitor means and resistor means being selected such that said transistor means is driven to conduction to apply a driving pulse to said driving coil in response to each of said pulses induced in said detecting coil of a selectedpolarity.

Claims (2)

1. An electric watch comprising an oscillating balance wheel having a shaft and a pair of spaced discs mounted on said shaft; two pairs of permanent magnets, one of each of said pairs of permanent magnets being mounted on each of said discs in facing relation to the other of said permanent magnets, the permanent magnets of each of said pairs being polarized to produce a magnetic field in the gap therebetween extending in a direction opposite to the field in the gap between the other of said pairs of permanent magnets so as to form a closed magnetic circuit; a detecting coil; a driving coil, said detecting and driving coils being separate from said balance wheel and mounted in the gaps between said permanent magnets, said detecting coil being wound coaxially inside of said driving coil, said detecting and driving coils being positioned so that, at the center of oscillation of said balance wheel most of the magnetic flux of said field passing through each pair of said permanent magnets is interlinked with a respective side of said driving coil, and so that, at said center of oscillation, the magnetic flux interlinked with said detecting coil is substantially smaller than that interlinked with said driving coil; and driving circuit means including said driving and detecting coils, said driving circuit means being adapted to apply driving pulses to said driving coils in response to each pulse induced in said detecting coil of a selected polarity.
2. AN electric watch as recited in claim 2, wherein said driving circuit means includes transistor means having a base, emitter and collector; a voltage source, said driving coil and voltage source being connected in series with the emitter-collector path of said transistor means; and base circuit means including said detecting coil, capacitor means connected in series with said detecting coil and resistor means connected in parallel with said series connection of said detecting coil and capacitor means, the time constant of said capacitor means and resistor means being selected such that said transistor means is driven to conduction to apply a driving pulse to said driving coil in response to each of said pulses induced in said detecting coil of a selected polarity.
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US12789371A 1971-03-25 1971-03-25
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Cited By (3)

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US20190187624A1 (en) * 2017-12-20 2019-06-20 The Swatch Group Research And Development Ltd. Timepiece comprising a mechanical oscillator associated with a regulation system
US20190187625A1 (en) * 2017-12-20 2019-06-20 The Swatch Group Research And Development Ltd Timepiece comprising a mechanical oscillator associated with a regulation system
US11422510B2 (en) * 2017-12-20 2022-08-23 The Swatch Group Research And Development Ltd Timepiece comprising a mechanical oscillator associated with a regulation system

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US3365635A (en) * 1963-10-17 1968-01-23 Smith & Sons Ltd S Oscillating motor for horological instruments
US3524118A (en) * 1967-09-21 1970-08-11 Reich Robert W Electronic oscillating motor timepiece drive
US3518515A (en) * 1968-02-23 1970-06-30 Robert W Reich Electronic driving circuit

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20190187624A1 (en) * 2017-12-20 2019-06-20 The Swatch Group Research And Development Ltd. Timepiece comprising a mechanical oscillator associated with a regulation system
US20190187625A1 (en) * 2017-12-20 2019-06-20 The Swatch Group Research And Development Ltd Timepiece comprising a mechanical oscillator associated with a regulation system
US11422510B2 (en) * 2017-12-20 2022-08-23 The Swatch Group Research And Development Ltd Timepiece comprising a mechanical oscillator associated with a regulation system
US11846915B2 (en) * 2017-12-20 2023-12-19 The Swatch Group Research And Development Ltd Timepiece comprising a mechanical oscillator associated with a regulation system
US11868092B2 (en) * 2017-12-20 2024-01-09 The Swatch Group Research And Development Ltd Timepiece comprising a mechanical oscillator associated with a regulation system

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