US3678681A - Mechanically switched electric timepiece - Google Patents

Mechanically switched electric timepiece Download PDF

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Publication number
US3678681A
US3678681A US166499A US3678681DA US3678681A US 3678681 A US3678681 A US 3678681A US 166499 A US166499 A US 166499A US 3678681D A US3678681D A US 3678681DA US 3678681 A US3678681 A US 3678681A
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United States
Prior art keywords
contact pin
recited
circuit means
balance
mechanically switched
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Expired - Lifetime
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US166499A
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English (en)
Inventor
Toshiaki Saito
Toshihiko Oki
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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

Definitions

  • ABSTRACT An electric timepiece switched by a mechanical contact point including a pair of spaced balance wheels having at least two pairs of permanent magnets mounted thereon in spaced facing relation. Coil means are fixedly mounted between said two balance wheels. Mechanical contact means are provided in cluding actuating means mounted on said balance wheels for closing a circuit between said coil and an electric source dur-' ing a certain range of one reciprocation of said balance wheels to apply a driving energy to said magnet.
  • an electric timepiece switched by a mechanical contact point including a pair of spaced balance wheels, at least two pairs of permanent magnets mounted in facing relation on said pair of balance wheels, a coil fixedly mounted intermediate said pair of balance wheels in the path of said permanent magnets, electric source means, and mechanical means for electrically connecting said coil to said electric source means in response to the rotation of said balance wheels in a certain range of reciprocation of said balance wheels for the supply of driving energy to said magnets.
  • Said mechanical means may include a contact pin mounted on said balance wheels and a resilient contact point member fixedly mounted in said timepiece in the path of said contact pin for interconnecting said electric source means and said coil.
  • Said mechanical means may also include a hairspring for electrically connecting said contact pin to the circuit including said coil and electric source means.
  • Said contact pin may be positioned intermediate said two balance wheels.
  • a protective circuit means may be provided in the circuit including said mechanical contact means, said coil and said electric source means for preventing damage to said electrical contact means.
  • Said protective circuit means may include a diode connected in parallel with said coil, a condenser connected in parallel with said mechanical contact means, or a transistor connected with its base connected to said mechanical contact means and said coil connected in the emitter to collector path thereof.
  • Three spaced pairs of permanent magnets may be mounted on said balance wheel, the middle pair of said permanent magnets having an area of about twice the dimensions of the other two pairs of said magnets.
  • Said displaceable means may include a contact spring displaced by said contact pin into and out of engagement with said contact point member.
  • said contact pin is not a part of the electric circuit including the electric source means and said coil, but rather, serves to deflect a movable contact member connected in said circuit into engagement with a fixed contact pin to close said circuit.
  • the object of this invention is to provide an electric timepiece switched by a mechanical device wherein wear of the contact points of said mechanical device is minimized, the mechanism is compact, and power consumption is small.
  • a further object of this invention is to provide a mechanically switched electric timepiece the components of which are interchangeable with contactless electric timepieces.
  • FIG. 1 is a schematic representation of the relative sizes of balance wheels of mechanically switched electric timepieces wherein the permanent magnet is fixed, and wherein the permanent magnet is mounted on the balance wheel;
  • FIG. 2 is a cross-sectional view showing an electric timepiece wherein the coil is mounted on the balance wheel;
  • FIG. 3 is a cross-sectional view of a mechanically switched electric timepiece according to the invention.
  • FIG. 4 is a circuit diagram of the basic circuit of the arrangement of FIG. 3;
  • FIG. 5 is a circuit diagram of the basic circuit of the arrangement of FIG. 2;
  • FIGS. 6, 7 and 8 are circuit diagrams showing the circuit of FIG. 4 modified to incorporate protective circuits for the mechanical contact point;
  • FIGS. 9 and 10 are plan and side elevational views respectively of the balance wheels and magnets mounted thereon of an embodiment of the arrangement according to the invention.
  • FIG. 1 l is a partial plan view of another embodiment of the arrangement according to the invention.
  • the prior art mechanically switched electric watches include a balance wheel I having a coil 2 mounted in the periphery thereof.
  • a permanent magnet 3 is mounted on a fixed base such as the plate of the watch.
  • This arrangement requires contact points between the coil and the power source of the electric watch, but such prior art contact points were subject to substantial wear by abrasion, since it is difiicult to provide a protective circuit for such contact points as more particularly shown in FIG. 5.
  • the region surrounded by the dashed line represents the portion of the circuit mounted on the oscillating balance wheel, which portion includes the coil.
  • the capacitor In order to prevent sparking at the contact point, it would be necessary to position a diode at both ends of the coil, which would require mounting a diode on the balance wheel, an approach which would render unstable the moment of inertia of the balance wheel.
  • the use of a capacitor as a protective device is also nearly impossible, since the capacitor must be connected between the fixed and moving contacts, and only one terminal of the balance wheel can be connected to earth through a hairspring.
  • FIG. 2 Still a further disadvantage of the arrangement of FIG. 2 is the relative size of the balance wheel thereof, as exemplified in FIG. 1.
  • This must be compared with the balance wheel structure shown in phantom lines wherein the coil 6 is mounted on the balance wheel 7.
  • the relative sizes are shown for the case where the same driving energy is to be achieved, in other words, where the balance wheels are to have the same moment of inertia.
  • the mounting of the coil on the balance wheel increases the size of the timepiece.
  • Still a further clifliculty with the arrangement of FIG. 2 is the air losses, and the relative inefficiency of the electro-mechanical conversion thereof.
  • balance wheels 9 and 10 formed of magnetic material are mounted for common oscillation.
  • Two pairs of circumferentially spaced permanent magnets 11 and 12 are mounted in facing relation on the inner surfaces of balance wheels 9 and it] (see permanent magnets 4 and 5 or FIG. 1).
  • the spacing between the permanent magnets on each balance wheel substantially corresponds to the spacing of the arms of the coil 13 which is fixedly mounted in the region intermediate said balance wheels in the path of said permanent magnets.
  • a contact pin 14 is secured to balance wheel 9 and projects into the space intermediate the spaced balance wheels.
  • a contact spring 15 is positioned for engagement by contact pin 14 once during each reciprocation of the balance wheel.
  • the contact spring is insulated from the plate of the watch and is electrically connected'to a terminal 16.
  • Terminal 16 is electrically connected (not shown) to one end 17 of coil 13.
  • the other end 18 of said coil is connected to the negative pole of battery 19, the positive pole of which is grounded, contact pin 14 also'being connected to ground through a hairspring.
  • FIG. 4 The electric circuit of the arrangement of FIG. 3 is shown in FIG. 4, the portion of thecircuit mounted on the balance wheel being encircled by a dashed line. As is seen in FIG. 4, only. the contact pin 14 is mounted on the balance wheel.
  • FIGS. 6, 7 and 8 show various embodiments of protective circuits for protecting the contact points of the arrangement according to the invention. Since only one terminal of the circuit must be connected to a hairspring to the balance wheel the defects in the prior arrangements can be avoided.
  • diode 20 is connected across the coil so that the over current produced when the contact point is released passes in the direction of the arrows through said diode, to reduce the spark at the contact point and to protect said contact point.
  • the diode being compact in size, requires little space and is particularly favorable for use in wrist watches.
  • a condenser 21 is provided between the contact pin 14 and the spring contact 15, to provide low cost protection to the contact point.
  • a transistor is connected at its base to the contact lead, the coil being connected in the emitter-collector path of the transistor. When the contact point .is closed, the base current flows in the transistor, and the transistor is turned on to apply a driving current to the coil.
  • the base current is very small, the wear on the contact pin is very small, so that even if the resistance of the contact point is somewhat increased, the current is sufficient to drive the balance wheel due to the amplification of the transistor.
  • Mechanically switched electric timepieces are subject to substantial energy loss due to braking of the balance wheel at the mechanical contact point, so that a high driving efficiency is required to compensate for such losses.
  • a closed magnetic circuit is provided, permitting a reduction in size of the balance wheel, a high frequency of oscillation, and a resistance to external magnetic fields.
  • the provision of the mechanical contact point intermediate the pair of spaced balance wheels serves to reduce the thickness of the structure.
  • a further advantage of the arrangement according to the invention is that the components thereof are also adapted for use in electrically switched electric wrist watches which utilize driving circuits incorporating transistors or the like for switching the driving current into the driving coil, and which do not include mechanical contacts.
  • the driving coil is mounted on the balance wheel, it is difficult to modify a mechanically switched electric watch into a contact with an electric watch, since two separate hairsprings are required for providing electrical connection to the two terminals or the driving coil, and the use of two separate hairsprings increases the thickness of the watch.
  • the coil is fixed and the magnets are mounted on the balance wheel, conversion is relatively easy, so that similar components can be used in both contactless and mechanically switched watches.
  • FIG. 9 In the embodiment of the invention of FIG. 3, two pairs of permanent magnets are provided, and the electric current flows through the coil in only one direction, since the balance wheel is driven in only one direction in one reciprocation of the balance wheel. Ifthree pairs of magnets are provided, the balance wheel can be driven in both directions during one reciprocation of the balance wheel.
  • FIGS. 9 and 10 wherein three pairs of permanent magnets 22, 23 and 24 are positioned in facing relation on the inner surfaces of the balance wheels.
  • the respective magnetic circuits between the adjacent pairs of permanent magnets is shown by the arrows of FIG. 10. Ifthe area of the central magnet 22 is twice as large as the area of magnets 23 and 24, the magnetic flux is most efficiently utilized, and the lightest configuration of the balance wheel is produced. Note that the spacing between the adjacent pairs of the permanent magnets is such as to encompass the arms of the coil 25, as shown in FIG. 9.
  • FIG. ll A further embodiment of the arrangement according to the invention as shown in FIG. ll, wherein the contact pin mounted on the balance wheel is not utilized to directly provide an electrical contact through a hairspring. Rather, contact pin 26 on the balance wheel serves only to displace contact spring 28, but not as an elecu-ical contact itself.
  • the electrical connection is made between contact spring 28 and a second contact pin 27 disposed on base plate 30, when contact spring 28 is displaced to the position 29 shown in phantom lines by contact pin 26. Since both the contact spring and the second contact pin are positioned on the base plate 30, even if the contact point is worn and poor contact results, the balance wheel need not be replaced in order to correct the defect, it being sufficient merely to change the contact point mechanism, an arrangement particularly advantageous for after-sales service.
  • a mechanically switched electric timepiece comprising a pair of spaced balance wheels mounted for common oscillation; at least two pairs of permanent magnets mounted in facing relation on said pair of balance wheels; a coil fixedly mounted intermediate said pair of balance wheels in the path of said permanent magnets; electric source means; circuit means for electrically connecting said coil to said electric source means; and mechanical means for selectively closing said circuit means in response to the rotation of said balance wheel in a certain range of reciprocation of said balance wheel for the supply of driving energy to said magnets.
  • a mechanically switched electric timepiece as recited in claim 1, wherein said mechanical means includes a contact pin mounted on said balance wheel and forming a part of said circuit means and a resilient contact point member fixedly in the path of said contact pin and forming a part of said circuit means for engagement by said contact pin in said certain range of reciprocation of said balance wheels.
  • said protective circuit means includes transistor means having a base, emitter and collector, said coil being connected in the emitter to collector path of said transistor, the portion of said circuit means including the contact point between said contact pin and said contact point member being in the base circuit of said transistor means.
  • a mechanically switched electric timepiece as recited in claim 1, wherein said mechanical means includes a first contact pin mounted on said balance wheels, a resilient contact point member fixedly mounted in the path of said contact pin for displacement thereby, and a second contact pin fixedly mounted in the path of displacement of said resilient contact point member, said contact point member and said second contact pin forming part of said circuit means for closing said circuit to supply driving energy to said magnets.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Electromechanical Clocks (AREA)
  • Permanent Magnet Type Synchronous Machine (AREA)
US166499A 1970-07-29 1971-07-27 Mechanically switched electric timepiece Expired - Lifetime US3678681A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6601470 1970-07-29

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US3678681A true US3678681A (en) 1972-07-25

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US166499A Expired - Lifetime US3678681A (en) 1970-07-29 1971-07-27 Mechanically switched electric timepiece

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US (1) US3678681A (enExample)
DE (1) DE2138028A1 (enExample)
FR (1) FR2099667B1 (enExample)
GB (1) GB1345410A (enExample)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3924401A (en) * 1973-03-28 1975-12-09 Egon Heim Torsion pendulum clock
US9778619B2 (en) * 2013-02-04 2017-10-03 Montres Breguet Sa Magnetic or electrostatic pivoting of a mobile timepiece element

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3184910A (en) * 1962-07-10 1965-05-25 Lip Sa Electric watches
FR1473362A (fr) * 1966-02-22 1967-03-17 Citizen Watch Co Ltd Dispositif d'entraînement de balancier de montre et montres et appareils similaires équipés d'un tel dispositif
CH458219A (de) * 1964-04-08 1968-01-31 Kienzle Uhrenfabriken Gmbh Zeithaltendes Gerät
US3590573A (en) * 1968-02-19 1971-07-06 Hatot Leon Ets System for synchronising timing devices
US3605401A (en) * 1968-09-15 1971-09-20 Reich Robert W Electronically powered clock

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR94561E (fr) * 1966-05-16 1969-09-12 Leblanc Albert Georges Alternateur hétéropolaire a fer tournant.

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3184910A (en) * 1962-07-10 1965-05-25 Lip Sa Electric watches
CH458219A (de) * 1964-04-08 1968-01-31 Kienzle Uhrenfabriken Gmbh Zeithaltendes Gerät
FR1473362A (fr) * 1966-02-22 1967-03-17 Citizen Watch Co Ltd Dispositif d'entraînement de balancier de montre et montres et appareils similaires équipés d'un tel dispositif
US3590573A (en) * 1968-02-19 1971-07-06 Hatot Leon Ets System for synchronising timing devices
US3605401A (en) * 1968-09-15 1971-09-20 Reich Robert W Electronically powered clock

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3924401A (en) * 1973-03-28 1975-12-09 Egon Heim Torsion pendulum clock
US9778619B2 (en) * 2013-02-04 2017-10-03 Montres Breguet Sa Magnetic or electrostatic pivoting of a mobile timepiece element

Also Published As

Publication number Publication date
GB1345410A (en) 1974-01-30
FR2099667B1 (enExample) 1975-02-07
DE2138028A1 (de) 1972-02-10
FR2099667A1 (enExample) 1972-03-17

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