US3660737A - Magnetic escapement - Google Patents

Magnetic escapement Download PDF

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Publication number
US3660737A
US3660737A US84324A US3660737DA US3660737A US 3660737 A US3660737 A US 3660737A US 84324 A US84324 A US 84324A US 3660737D A US3660737D A US 3660737DA US 3660737 A US3660737 A US 3660737A
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US
United States
Prior art keywords
oscillator
magnetic
escape wheel
transistor
rotor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US84324A
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English (en)
Inventor
Satoshi Sakai
Kenzo Shirakawa
Norio Shimizu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Electric Works Co Ltd
Original Assignee
Matsushita Electric Works Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP10869769U external-priority patent/JPS5011413Y1/ja
Priority claimed from JP44093753A external-priority patent/JPS492927B1/ja
Application filed by Matsushita Electric Works Ltd filed Critical Matsushita Electric Works Ltd
Application granted granted Critical
Publication of US3660737A publication Critical patent/US3660737A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • G04C3/08—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 mechanical oscillator other than a pendulum or balance, e.g. by a tuning fork, e.g. electrostatically
    • G04C3/10—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 mechanical oscillator other than a pendulum or balance, e.g. by a tuning fork, e.g. electrostatically driven by electromagnetic means
    • G—PHYSICS
    • G04—HOROLOGY
    • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C5/00—Electric or magnetic means for converting oscillatory to rotary motion in time-pieces, i.e. electric or magnetic escapements
    • G04C5/005—Magnetic or electromagnetic means
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/15—Intermittent grip type mechanical movement
    • Y10T74/1502—Escapement

Definitions

  • a magnetic escapement including a rotor driven by an external force. and escape wheel made ofa magnetic material and [2i] 84,324 having along its periphery radially extending magnetic teeth,
  • said escape wheel being coupled through a coil spring to the rotor, and an oscillator havin a ma netic ole iece secured [30) Foreign Application Priority Dam at the end of one of its tines 5nd cofipled agnstically to the Nov. 15 I969 escape wheel teeth.
  • the oscillator is preferably formed in a W- Nov. [8, 1969 Nov. 2i, 1969 shape and supported at a point near its center of gravity for exn a D. a J
  • a driving circuit of a constant output for the rotor which includes a compensating transistor and a temperature compen- [52] US. [Si] Int.
  • Sheets-Sheet 4 29 fil fi --H- 0 ii i b i 5 ed;
  • Fig. 8 MAGNETIC ESCAPEMENT This invention relates to improvements in magnetic escapements used in such devices specifically as electric clocks or the like in which a constant velocity is required.
  • the above mentioned defect is removed with an arrangement by which the escape wheel and driving shaft of the wheel are coupled by a spring having a low rigidity. That is, the external shocks are effectively absorbed by the resiliency of said spring and any deviation from the normal relative position of the oscillator to the escape wheel is also damped by the resiliency of the spring, whereby the defect that the magnetic couple is readily broken is effectively avoided.
  • a main object of the present invention is therefore to provide an improved magnetic escapement which is stable against any external shocks and produces constant rotation at uniform speed, causing less likelihood of mis-synchronization.
  • Another object of the present invention is to provide a magnetic escapement having a large exciting force and may be made in compact form.
  • a further object of the present invention is to provide a magnetic escapement which is capable of adjusting the speed of the escape wheel.
  • FIG. 1 is a perspective view of the magnetic escapement according to the present invention.
  • FIG. 1B shows a circuitry diagram of a driving circuit for the escapement.
  • FIG. 2 is a plan view showing partly in section the main part of the escapement in FIG. 1.
  • FIG. 3 is a vertical view showing partly in section the main part in FIG. 2.
  • FIG. 4 is a vertical section of escape wheel unit showing details of the same.
  • FIG. 5 is a diagram showing resonance curve of the oscillator used in the present invention.
  • FIGS. 6 8 are circuitry diagrams of conventional driving circuits for the magnetic escapement.
  • FIGS. 9 and 10 show diagrammatically voltage-current characteristics at the collector and base of the transistor used in the driving circuit, respectively.
  • FIG. 11 is a diagram showing voltage characteristics.
  • FIG. 12 is a diagram showing output variations with respect to temperatures.
  • l is an oscillator or oscillating governer, which is formed substantially in a W-shape as shown in FIG. 3 and is fixed to a supporting member 8 at the center of gravity, shown at 17, of the oscillator l.
  • the supporting member 8 is secured to a fixed base 16 by means of screws [8, and said base 16 in turn is secured to a frame plate l5.
  • 9 is a dead weight secured to a free end of the supporting member 8.
  • the oscillator 1 is provided with a permanent magnet 2 and a balance weight 2' made of a magnetic material, respectively secured to each free end of the oscillator I.
  • 3 is an escape wheel, of which details are shown in FIG. 4. That is, the escape wheel 3 is secured to a boss 7, which is fixed to a driving shaft 6.
  • 4 is a rotor consisting of a cylindrical permanent magnet in which N and S poles are alternately arranged along its peripheral surface. Said rotor 4 is fixed around a sleeve 12 which is mounted over the driving shaft 6 for free rotation therearound.
  • the sleeve 12 is provided ad jacent the lower end with a threaded part 12' for starting the rotor.
  • 13 is a driving gear secured to the shaft 6 and the sleeve 12 rests on the upper surface ofthe gear 13.
  • I1 is a coil spring, which is fixed at an end to the escape wheel 3 and at the other end to the rotor 4. 22 is a worm gear fixed on the shaft 6.
  • means for supporting the driving shaft 6 is provided in the form of a pair of pedestal plates 14 and 14', respectively formed by bending a part of the frame plate 15 at right angles thereto, so as to support the shaft 6 between said plates 14 and 14' for free rotation.
  • a further frame plate 20 is arranged in parallel relation to the frame plate 15 and is secured thereto by means of screws through spacers 19.
  • the worm 22 is in mesh with a gear wheel 23, which in turn is in mesh with a gear 24, so that the escapement is connected to a gear system for driving hour-hand, minutehand and secondhand.
  • the coil assembly 5 is mounted to the frame plate 15 by means of screws 26 through an insulating board 25.
  • a speed adjusting member 34 made of a magnetic material is provided adjacent the permanent magnet 2 mounted on the tine of the oscillator I.
  • the member 34 is fixed on an adjusting screw 35, which is screwed at one end into a threaded hole of the frame plate 15 so that the position of the speed adjusting member 34 will be varied by turning the screw 35, thereby influencing the specific frequency of the oscillator I so as to vary it and consequently the number of rotation of the escape wheel 3.
  • the escape wheel 3 is made of a magnetic material and is provided with radial magnetic teeth 36 at regular intervals.
  • the oscillator 1 is supported by means of the fixed base 16, so that its longitudinal axis will be parallel to the plane of the escape wheel 3 and the permanent magnet 2 secured to one of the tines of the oscillator 1 will be disposed above the escape wheel 3 so as to oppose that tooth 36 of the wheel 3 which is remote from the fixed base 16.
  • 21 is a manual driving lever provided for kicking the threaded part 12' of the sleeve 12 and the driving gear l3 simultaneously so that the driving shaft 6 and rotor 4 will be started in the desired direction.
  • the oscillating governor or oscillator l is supported by the supporting member 8 which has the dead weight 9.
  • This dead weight 9 is provided for the purpose of reducing the amplitude of unnecessary oscillations of the oscillator 1, so that the accuracy of the oscillator is very high. That is, as diagrammatically shown in FIG. 3, in the case when the both tines of the oscillator are oscillated in the same phase, that is, in the asymmetrical mode at a lower specific frequency f, the oscillation amplitude is relatively smaller than in the case of the reverse phase or symmetrical mode oscillation at a higher specific frequency f,.
  • the resonance sharpness value at the frequency f is low and the oscillator is unable to accomplish higher accuracy while it oscillates at this frequency.
  • the oscillation frequency is low, such as f
  • the output of the rotor rotating at the speed corresponding to this frequency f 1 is insufficient and hence the motor is no longer rotatable and, consequently, the synchronized rotation of the wheel 3 is no longer established.
  • the weight 9 having a suitable weight for absorbing such oscillation of the frequency f, is provided at the opposite end of the supporting member 8 to a connecting part 8' with respect to the supporting point I7.
  • FIG. 1B an electric circuit for controlling the coil assembly 5 in the magnetic escapement of FIG. 1 is shown.
  • 27 is a detecting coil and 28 is a driving coil. These two coils 27 and 28 are wound as stacked so as to form the coil assembly 5.
  • 29 is a PNP type transistor
  • 30 is a compensating NPN type transistor.
  • 3l is a condenser for preventing parastic oscillation
  • 32 is a DC source.
  • 33 is a temperature compensating element.
  • An end a of the detecting coil 27 is connected to the base of the transistor 29 and the other end I: is connected to an end of the driving coil 28 and also to the emitter of the transistor 29.
  • the other end d of the driving coil 28 is connected to the collector of of the compensating transistor 30.
  • the base of the transistor 29 and the emitter of the transistor 30 are connected to each other through the temperature compensating element 33. and between the collector of the transistor 29 and the collector of the transistor 30 the DC. source 32 is inserted.
  • the condenser 31 is inserted between the base and collector of the transistor 29.
  • the driving shaft 6 and the permanent magnet rotor 4 are started in a fixed rotating direction, so that the rotor 4 begins to rotate. Since the escape wheel 3 is coupled to the rotor 4 through the coil spring 11, the rotation of the rotor 4 is transmitted to the wheel 3 and thus the wheel 3 is also caused to rotate together with the rotor. As the escape wheel 3 is thus rotated, the oscillator I carrying at a tine thereof the permanent magnet 2 which is magnetically coupled to the magnetic teeth of the wheel is excited by the teeth each time a tooth passes beneath the magnet 2. Here, at the time when the frequency of this excitation coincides with the specific frequency of the oscillator 1. the oscillator 1 will be in its resonant state. The escape wheel 3 is restricted, at this time, to a speed conforming with the specific frequency of the oscillator I.
  • the speed adjusting member 34 made of a magnetic material is mounted on a movable screw 35 in the oscillating direction of the oscillator I, so that the member 34 is located at a position opposite to one of the poles of the permanent magnet 2 in attractive relation to the latter and is movable together with the screw 35. If the speed adjusting member 34 is moved so as to vary the attracting force acting between the member 34 and magnet 2. the specific frequency of the oscillator l is caused to vary. Therefore, it is possible to adjust the number of revolutions per unit time period of the escape wheel 3.
  • FIGS. 6. 7 and 8 show conventional driving circuits.
  • the detecting coil 27 is inserted between the base and the emitter of the transistor 29, the DC. source 32 and driving coil 28 are connected in series between the collector and the emitter of the transistor 29, and the parastic oscillation preventing condenser 31 is connected between the base and the collector of the transistor 29.
  • an NPN type transistor is used for the transistor 29, and a DC. blocking condenser 36 and a bias resistance 37 are used.
  • the collector voltage is varied from i to i in the collector voltage V collector current I characteristics shown in FIG. 9. and consequently the circuitry output is increased. If the voltage is decreased, on the other hand. in the case when a biasing circuit is accompanied or the transistor is made to operate close to its saturation point. the voltage is varied from E. to E, and the collector current is varied from i to i in the V l characteristics of FIG. 9, so that the circuitry output is decreased. Further, in the case when the transistor is unsaturated, even a slight variation of the base current will influence the output. In order to prevent this, there has been suggested such a circuit as shown in FIG. 8.
  • the compensating current i is determined by the voltage V across base and emitter and the resistance value of the temperature compensating element 33.
  • the state of the compensation shall be explained now in detail.
  • the V, I characteristics of the transistor are changed to the state of the broken line shown in FIG. 10 and the base current is increased from i to i
  • the compensating current i is also made to be increased so as to make the base current of the transistor 29 constant. It is possible to further compensate for possible differences between the respective characteristics of the transistors 29 and 30. That is, for the temperature compensating element 33, either type of such element having positive or negative temperature coefficient is used depending on the requirement.
  • the motor speed is increased and the induction voltage of the detecting coil 27 is increased, so that the base current i is increased.
  • the respective terminal voltages e, and e of the detecting coil 27 and driving coil 28 are increased. Due to these increases. the emitter-base voltage V of the compensating transistor 30 is also increased, so that the compensating cur rent i, is made to increase so that the base current i of the transistor 29 is not increased and, thus, the motor speed can be kept at a constant rate.
  • the solid line curve shows the case of the present invention and the broken line curve shows the conventional case. As is clear from the curves, an excellent result has been obtained according to the present invention.
  • the diagram shown in FIG. 12 shows output variations due to the temperature, in which the broken line curve shows the case where no compensating means is used.
  • the driving shaft 6 and the escape wheel 3 are coupled by means of the coil spring I] which is low in rigidity and, therefore. any shocks given from outside the device are softened (or absorbed) by the resiliency of the coil spring, so that no large influence will be exerted upon the magnetic coupling of the escape wheel to the oscillator.
  • the oscillator is arranged in such manner that its longitudinal axis will be parallel to the plane of escape wheel and that at least one of its forward ends will be positioned adjacent the tooth of the escape wheel which is remote from the supporting point of the oscillator. Therefore, it is possible to make the dimension of the magnetic escapement smaller than in the conventional cases so that the forward end or ends of the oscillator will be positioned substantially at the center of the escape wheel or near the supporting point of the oscillator,
  • the compensating transistor is inserted in such manner that its base and collector are connected to the intermediate tap and collector side terminal of the driving coil, respectively, and the emitter of this transistor is connected through the temperature compensating element to the base of the transistor. Therefore, any variations in the prevailing temperature will be compensated for by the temperature characteristics of the compensating transistor and temperature compensating element, and any variations in the load will be compen sated for by the compensating transistor with a detection of the voltage at the detecting coil and driving coil, whereby the output of the driving circuit may always be stable.
  • a magnetic escapement comprising a rotor, means providing a force for rotating said rotor, an escape wheel, a coil spring for coupling said escape wheel to said rotor, said escape wheel being formed of a magnetic material and having a plurality of magnetic teeth extending radially from the peripherey thereof at regular intervals, an oscillator extending in a direction parallel to said escape wheel, means for supporting said oscillator, and a permanent magnet at one only of the forward ends of said oscillator for oscillation in a direction parallel to the plane of the escape wheel.
  • a magnetic escapement as claimed in claim 1 wherein said oscillator is formed substantially in a Wshape and is supported by said support means at a position near its center of gravity, and further comprising a weight attached to the other of said forward ends of said oscillator, said weight being suffi cient to absorb the specific frequency corresponding to the frequency in the asymetrical mode.
  • a magnetic escapement as claimed in claim I wherein said permanent magnet is provided with a magnetic pole at each end thereof, one of said poles being opposed to the magnetic force of the said escape wheel and further comprising means for adjusting the speed of oscillation of said oscillator made of a magnetic material and movable in the oscillating direction of said oscillator, the other of the poles of said permanent magnet being opposed to the magnetic force of said adjusting means.
  • said means for rotating said rotor comprises a rotor driving circuit including a first transistor, a detecting coil connected between the emitter and base of said first transistor, a driving coil connected in series with said detecting coil for exciting said rotor and connected between the emitter and collector of said first transistor through a source of current, the junction point of said detecting coil and driving coil being connected to the emitter of said irst transistor, a second compensating

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Reciprocating, Oscillating Or Vibrating Motors (AREA)
  • Electromechanical Clocks (AREA)
  • Dynamo-Electric Clutches, Dynamo-Electric Brakes (AREA)
US84324A 1969-11-15 1970-10-27 Magnetic escapement Expired - Lifetime US3660737A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP10869769U JPS5011413Y1 (de) 1969-11-15 1969-11-15
JP9233969 1969-11-18
JP44093753A JPS492927B1 (de) 1969-11-21 1969-11-21

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US3660737A true US3660737A (en) 1972-05-02

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Application Number Title Priority Date Filing Date
US84324A Expired - Lifetime US3660737A (en) 1969-11-15 1970-10-27 Magnetic escapement

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US (1) US3660737A (de)
DE (1) DE2052941C3 (de)
FR (1) FR2067320B1 (de)
GB (1) GB1338084A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4332199A (en) * 1980-06-09 1982-06-01 The United States Of America As Represented By The Secretary Of The Navy Electromagnetic arming rate regulator
US5025428A (en) * 1990-12-17 1991-06-18 Wit Jarochowski Electromagnetic escapement for mechanically driven watch or clock
US20030090962A1 (en) * 2000-04-11 2003-05-15 Xuan-Mai Tu Escapement device for timepiece component

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2311445C3 (de) * 1973-03-08 1985-03-14 Vdo Adolf Schindling Ag, 6000 Frankfurt Elektrische Uhr mit Einphasenschrittmotor

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2946183A (en) * 1955-06-14 1960-07-26 Horstmann Magnetics Ltd Self-starting magnetic escapement mechanisms
US3137122A (en) * 1962-01-04 1964-06-16 Amphenol Borg Electronics Corp Resilient means for driving escape wheel
US3208287A (en) * 1961-10-21 1965-09-28 Jeco Kk Magnetic escapement

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1366980A (fr) * 1963-06-10 1964-07-17 Diehl Fa Amplificateur de commande à transistor, en particulier pour l'application à des commandes d'entraînement d'horloges à réglage automatique
US3303705A (en) * 1964-03-19 1967-02-14 Bulova Watch Co Inc Attitude compensated electromechanical oscillator
GB1195432A (en) * 1967-05-15 1970-06-17 Horstmann Magnetics Ltd Electromechanical Oscillators

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2946183A (en) * 1955-06-14 1960-07-26 Horstmann Magnetics Ltd Self-starting magnetic escapement mechanisms
US3208287A (en) * 1961-10-21 1965-09-28 Jeco Kk Magnetic escapement
US3137122A (en) * 1962-01-04 1964-06-16 Amphenol Borg Electronics Corp Resilient means for driving escape wheel

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4332199A (en) * 1980-06-09 1982-06-01 The United States Of America As Represented By The Secretary Of The Navy Electromagnetic arming rate regulator
US5025428A (en) * 1990-12-17 1991-06-18 Wit Jarochowski Electromagnetic escapement for mechanically driven watch or clock
US20030090962A1 (en) * 2000-04-11 2003-05-15 Xuan-Mai Tu Escapement device for timepiece component
US6712500B2 (en) * 2000-04-11 2004-03-30 Detra Sa Escapement device for timepiece

Also Published As

Publication number Publication date
FR2067320B1 (de) 1974-03-01
DE2052941A1 (de) 1971-06-09
FR2067320A1 (de) 1971-08-20
DE2052941C3 (de) 1974-02-07
GB1338084A (en) 1973-11-21
DE2052941B2 (de) 1973-07-12

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