US3652955A - Electromechanical oscillator using electret coupling - Google Patents
Electromechanical oscillator using electret coupling Download PDFInfo
- Publication number
- US3652955A US3652955A US59653A US3652955DA US3652955A US 3652955 A US3652955 A US 3652955A US 59653 A US59653 A US 59653A US 3652955D A US3652955D A US 3652955DA US 3652955 A US3652955 A US 3652955A
- Authority
- US
- United States
- Prior art keywords
- mechanical element
- arrangement
- electret
- pick
- electrical energy
- 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
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Classifications
-
- 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
-
- 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
- G04C3/02—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 pendulum
- G04C3/024—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 pendulum using other coupling means, e.g. electrostrictive, magnetostrictive
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
- H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
- H03B5/30—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator
Definitions
- An electrically driven oscillator device is provided with one or more electrets for establishing electrostatic coupling between a mechanical oscillating element and an electrical drive.
- the mechanical oscillating element can comprise a reed, a tuning fork, a pendulum, or a hair-spring balance wheel.
- the electrical drive can be an AC voltage source or an electronic feedback circuit. 1n electrically driven devices, electrets can be used in both the pickup and driving circuits to eliminate hysteresis. Alternatively, in order to isolate the pickup circuit from the driving circuit, electrets can be used in only one of these circuits and magnetic arrangements can be used in the other.
- FIG. 4C 'SHEET 2 BF 3 2" AMPLIFIER DRAIN SUBSTRATE SOURCE .JI- T 400
- FIG. 4C
- the present invention relates to an electrically driven oscillatory device which utilizes one or more electrets to establish electrostatic coupling between a mechanical oscillating element and an electrical drive.
- Electrically driven oscillatory devices are useful in a variety of applications such as timekeeping devices and high-Q oscillators.
- Such devices typically comprise a mechanical element capable of periodic oscillation which is magnetically coupled to an electrical drive by interacting electromagnets and permanent magnets.
- the oscillating element can comprise any one of a number of known mechanical elements, such as a reed (U.S. Pat. No. 2,036,917 issued to M. P. Favre-Bull, Mar. 8, 1935), a tuning fork (British Pat. No. 155,854 issued to W. H. Eccles et al., Jan. 6, 1921), a pendulum (French Pat. No. 1,092,411 published Apr. 21, 1955), or a hairspring balance wheel (U.S. Pat. No. 2,769,946 issued to H. D. Brailsford, Nov. 6, 1956).
- the electrical drive can comprise an AC source, a transistor amplifier, or vacuum-tube amplifier.
- a typical AC driven oscillatory motor is illustrated by the F avre-Bull device which comprises, in essence, a spring reed fixed at one end and a permanent magnet attached at the other end.
- the reed is mounted so that one pole of the magnet is disposed between the two poles of a curved electromagnet.
- the reed is driven back and forth as the polarity of the electromagnet alternates.
- a typical electronic oscillatory motor is illustrated by the device disclosed in U.S. Pat. No. 2,971,323 issued to M. Hetzel, Feb. 14, 1961.
- the Hetzel device comprises a tuning fork having a pair of permanent magnets attached to its tines for interacting with separate pickup and driving coils.
- the pickup coil is connected to the input terminals of a transistor amplifier, and the driving coils are connected to the amplifier output terminals.
- the vibrations of the fork move one of the magnets into the pickup coil and induce a voltage which is applied to the input terminals.
- the input voltage becomes sufficiently large, it triggers a current pulse which passes through the drive coil and augments the vibration of the fork.
- FIG. 1 is a schematic cross section of an AC driven oscillating reed in accordance with the invention
- FIG. 2 is a schematic cross section of an electronically driven tuning fork in accordance with the invention.
- FIG. 3 is a schematic cross section of an electronically driven pendulum
- FIGS. 4A, 4B, and 4C illustrate a first example of a balance wheel oscillator device in accordance with the invention
- FIGS. 5A and 5B illustrate a second balance wheel device in accordance with the invention which is adapted to utilize both electrostatic attraction and repulsion in driving the wheel;
- FIGS. 6A and 6B illustrate yet another example of an electronically driven balance wheel
- FIG. 7 is a graphical illustration useful in understanding the embodiment of the invention shown in FIG. 6.
- FIG. 1 illustrates an oscillating reed device comprising an oscillating reed 100, such as a blade of spring steel, having one end fixed to a stationary base 101 and the other end attached to a pair of electrets 102 and 103.
- the electrets are disposed midway between a pair of electrodes 104 and 105 which, in turn, are electrically coupled to a source 106 of AC voltage, such as an outlet for volt, 60 cycle per second line voltage.
- Means such as the well-known pawl and ratchet wheel arrangement, are provided for converting oscillatory motion of the reed into rotary motion.
- a pair of stops 109 and 110 are fastened at suitable positions on a stationary frame (not shown) for limiting the amplitude of the reed and preventing the electrets from contacting the electrodes.
- Electrets are dielectric materials in which a permanent state of electrostatic polarization has been established by the displacement of the positive charges in constituent atoms with reference to negative charges. They were first described by Heaviside in 1892. Electrets are typically produced by subjecting a dielectric material, such as Mylar, polycarbonate, or polytetrafiuoroethylene to heat in the presence of a high electric field. The dielectric is then permitted'to cool while the field is applied. The properties of and the methods for fabricating electrets are explained in detail in the literature of the art. See, for example, U.S. Pat. No. 3,1 18,022 issued to G. M. Dessler on Jan. 14, 1964.
- the application of an AC voltage across electrodes 104 and 105 drives the reed back and forth as the electrodes change polarity.
- This oscillatory motion is converted into rotary motion by the pawl and ratchet wheel arrangement and can be used, for example, to drive the gear train (not shown) of an electric clock.
- the primary advantage of this device over typical prior art structures is its simplicity. No curved electromagnets with wound coils of copper wire or heavy laminated steel cores are required. In addition, the losses and distortion associated with hysteresis and eddy currents are avoided.
- FIG. 2 shows an example of an electronically driven tuning fork in accordance with the invention comprising, in essence, atuning fork coupled to both the input terminals of an amplifier and the output terminals, wherein at least one of the coupling arrangements includes one or more electrets.
- both the input and the output terminals are coupled to the fork by electret arrangements.
- a tuning fork 201 having tines 202 and 203 is rigidly attached by its base 204 to a stationary baseplate 205.
- Tine 202 of the fork is provided with electret means, such as a pair of electrets 206 and 207 attached to an extension 208 affixed to the tine, for electrostatically coupling the tine to an electronic drive circuit.
- the amplifier can comprise an NPN-transistor T, a DC voltage source V and a resistor R in a common base arrangement.
- NPN-transistor T a DC voltage source V
- resistor R a resistor
- the amplifier output terminals 214 and 215 are electrically connected to a pair of drive electrodes 216 and 217 disposed adjacent to a second pair of electrets 210 and 219 which are attached to an extension 220 affixed to tine 203.
- the polarities of the electrets and the electrodes are chosen and adapted to provide a drive signal of suitable polarity for sustaining oscillations of the fork.
- a pawl 221 and a ratchet wheel 222 are provided for converting oscillations of the fork into useful rotary motion.
- the vibration of tine 202 moves electrets 206 and 207 back and forth with respect to electrodes 209 and 210.
- This motion produces an alternating voltage across resistor R which is applied to the input terminals of amplifier 213.
- amplifier 213 is chosen or adapted to have a minimum threshold voltage so that the pickup voltage signal triggers either an attracting drive pulse to the drive electrodes just before electrets 218 and 219 reach the position of alignment with the drive electrodes or a repelling drive pulse just as they pass this position.
- the circuitry can be designed to provide both types of driving pulses, as will be shown below.
- attracting pulses are applied to the drive electrodes. In this manner, electrical energy from the amplifier is used to sustain oscillations in the fork.
- the primary advantage of this device is the elimination of the loss and distortion due to hysteresis and eddy currents.
- a secondary advantage is the savings in cost due to the elimination of the coils used in prior art devices.
- FIG. 3 shows a schematic side view of an electronically driven pendulum in accordance with the invention comprising a rod 300 pivotally mounted at one end to a support member 301 and attached to a transverse member 302 at the other end.
- the transverse member includes electret means comprising, for example, a pair of oppositely oriented electrets 303 and 304 for coupling to a pair of pickup electrodes 305 and 306 and another pair of electrets 307 and 308 for coupling to a pair of drive electrodes 309 and 310 for electrostatically coupling the pendulum to an electronic drive circuit.
- the electrets, pickup electrodes, and drive electrodes are advantageously positioned so that the electrodes and electrets overlap at the pendulum rest position.
- the electronic circuitry for this device is substantially the same as that described in connection with FIG. 2.
- the movement of electrets 303 and 3041 through the pickup electrodes 305 and 306 induces alternat ing voltage pulse across resistor R, applied to the input terminals of amplifier 213.
- the output of the amplifier is applied to the drive electrodes 309 and 310 to sustain oscillations in the pendulum.
- the oscillatory motion of the pendulum is converted into useful rotary motion by the pawl and ratchet wheel arrangement, and stops are provided for maintaining the amplitude of the pendulum within useful limits.
- FIGS. 4A and 4B illustrate, respectively, perspective and cross section views of a first example of a balance wheel oscillatory device in accordance with the invention.
- This device comprises, in essence, a balance wheel oscillator including electret means for coupling the balance wheel to an electronic drive circuit.
- the device comprises a balance wheel 400 rigidly attached to a rotatably mounted shaft 401 and elastically attached to at least one of a pair of fixed members (stators) 402 and 403 by a hairspring 404.
- Stator 102 is provided with a pickup electrode 405, and stator 403 is provided with a drive electrode 406.
- Balance wheel 4100 is provided with electret means comprising pickup electret 4107 and drive electret 408 for electrostatically coupling with electrodes 405 and 406, respectively. It is also provided with conductive means which act as a common ground electrode with respect to the pickup and drive electrodes.
- the balance wheel is conveniently made of a conductive material such as a metal and is provided with electrical contact means such as terminal 409 attached to a metal hairspring 404.
- Shaft 401 extends through stator 402 and is mechanically coupled to means, such as gear 410, for turning a ratchet wheel.
- the electronic drive circuitry is substantially the same as that described previously. It comprises, in essence, an electronic amplifier preferably comprising a metal-oxide-silicon field effect transistor (henceforth MOSFET) having its input terminals electrically connected between balance wheel 400 and pickup electrode 405 (which acts as the pickup electrode). The amplifier output is connected between the balance wheel and electrode 406, and electret 400 is appropriately driven by the output voltage.
- an electronic amplifier preferably comprising a metal-oxide-silicon field effect transistor (henceforth MOSFET) having its input terminals electrically connected between balance wheel 400 and pickup electrode 405 (which acts as the pickup electrode).
- the amplifier output is connected between the balance wheel and electrode 406, and electret 400 is appropriately driven by the output voltage.
- FIG. 1C illustrates the preferred circuit arrangement for using an N-channel MOSFET however, as is easily seen, a P- channel MOSFET can be used with only minor circuit modifications.
- FIG. 5A shows a schematic cross section of a second balance wheel device in accordance with the invention which is especially adapted to utilize both electrostatic attraction and repulsion in driving the wheel.
- the device is substantially the same as that shown in FIGS. 4A and 413 except that the balance wheel is provided with an electrically separate reference electrode for the pickup and the drive electrets. This is accomplished by using a balance wheel comprising a pair of metal discs 500A and 50013 mechanically connected by an insulator 500C.
- separate electrical contacts 509A and 50913 are conveniently provided by use of a pair of hairsprings 5041A and 5048.
- the remaining components are substantially identical to their counterparts previously described in connection with FIG. -1.
- the electronic drive circuit for use with this embodiment of the invention is chosen or adapted to supply an attracting voltage pulse to the drive electrode as the drive electret ap proaches the point of maximum overlap and a repelling voltage as it passes this point.
- the pickup electrode is electrically connected to the input terminals of two amplifying means, one such amplifying means for applying an attracting pulse to the drive electrode as the pickup electret approaches the pickup electrode and the other amplifying means for applying a repelling pulse as the pickup electret passed the pickup electrode.
- the pickup and the drive electrets are, of course, positioned so that they each approach their respective electrodes at the same time.
- a preferred embodiment of such a drive circuit is shown in FIG. 5B.
- the amplifying means for applying the attracting pulse comprises a pair of N-channel MOSFETS T and T and the amplifying means for applying the repelling pulse comprises a pair of P-channel MOSFETS T and T
- an electronically driven balance wheel is shown in schematic perspective and cross section views in FIGS. 6A and 68, respectively.
- an electret pickup arrangement is used in conjunction with a magnetic drive arrangement.
- a specially shaped electrode or electret is used to prevent activation of the magnetic driving arrangement against the motion of the oscillator.
- the device comprises a balance wheel 600 rigidly affixed to a rotatably mounted shaft 601 and elastically attached to a stator 602 by a hairspring 603.
- the balance wheel is provided with electret means comprising electret 604 for electrostatically interacting with pickup electrode 605 attached to the stator and is also provided with permanent magnet means comprising a pair of magnets 609 and 607 for magnetically interacting with an electromagnet 608 attached to the stator.
- the electronic circuitry used with this device is simply an amplifier arrangement adapted to deliver a current pulse to electromagnet 608 for driving the balance wheel through the permanent magnets is response to an above-threshold voltage from the pickup electrode 605.
- the electrode (or electret) is shaped so that an above threshold voltage is produced during the forward oscillation but not during the return oscillation. This is accomplished by making the electrode roughly triangular shaped with a vertex pointing in the direction of forward oscillation.
- An oscillatory device comprising:
- electret means for electrostatically coupling said mechanical element and said means for applying electrical energy are provided.
- a device including means for producing rotary motion from oscillatory motion of said mechanical element.
- said means for applying electrical energy comprises a pair of electrodes for receiving an alternating voltage
- said electret means is attached to said mechanical element and disposed between said electrodes.
- a device according to claim 3 wherein said mechanical element is a reed.
- said means for applying electrical energy for sustaining periodic oscillations comprises a pickup arrangement responsive to the motion of said mechanical element, amplifying means responsive to the signal from said pickup arrangement for producing an electrical driving signal, and a driving arrangement for sustaining oscillation of said mechanical element.
- said pickup arrangement comprises at least one pickup electrode
- said electret mean for electrostatically coupling said mechanical element and said means for applying electrical energy comprises one or more electrets attached to said mechanical element for electrostatically interacting with said pickup arrangement.
- a device according to claim 6 wherein said mechanical element is a tuning fork.
- said driving arrangement comprises at least one driving electrode
- said electret means for electrostatically coupling said mechanical element and said means for applying electrical energy includes electret means attached to said mechanical element for interacting with said driving arrangement.
- said driving arrangement comprises electromagnet means
- said mechanical element includes permanent magnet means for interacting with said electromagnet.
- a device wherein said mechanical element is a balance wheel elastically coupled to at least one stator member.
- a device wherein said mechanical element is a balance wheel elastically coupled to at least one stator member.
- a device wherein said mechanical element is a balance wheel elastically coupled to at least one stator member.
- the amplifying means responsive to the signal from said pickup arrangement has a threshold voltage
- the pickup arrangement is designed to produce an abovethreshold signal during only one direction of oscillation.
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Abstract
Description
Claims (14)
Applications Claiming Priority (1)
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US5965370A | 1970-07-30 | 1970-07-30 |
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US3652955A true US3652955A (en) | 1972-03-28 |
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US59653A Expired - Lifetime US3652955A (en) | 1970-07-30 | 1970-07-30 | Electromechanical oscillator using electret coupling |
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Cited By (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3769531A (en) * | 1968-10-08 | 1973-10-30 | Proctor Ets | Electrostatic system for generating periodical mechanical vibrations |
US3961209A (en) * | 1972-07-20 | 1976-06-01 | Biviator S.A. | Oscillator for time measurement |
US4189699A (en) * | 1977-04-08 | 1980-02-19 | Mfe Corporation | Limited-rotation motor with integral displacement transducer |
US4224557A (en) * | 1977-07-13 | 1980-09-23 | Displaytek Corporation Of Sanko | Controlling unit for A.C. driving an electrostatic device |
USRE31062E (en) * | 1977-04-08 | 1982-10-19 | Mfe Corporation | Limited-rotation motor with integral displacement transducer |
US4507623A (en) * | 1981-11-20 | 1985-03-26 | Siemens-Albis Ag | Oscillating device with capacitive displacement pickup |
US4694235A (en) * | 1986-08-01 | 1987-09-15 | General Scanning, Inc. | Capacitive position sensor |
US5206448A (en) * | 1990-01-16 | 1993-04-27 | Yamaha Corporation | Musical tone generation device for synthesizing wind or string instruments |
US20030217637A1 (en) * | 2002-05-24 | 2003-11-27 | Shigeru Muramatsu | Performance apparatus |
US20060114541A1 (en) * | 2002-12-10 | 2006-06-01 | Van Beek Josef T M | Transducer and electronic device |
WO2012013374A1 (en) * | 2010-07-30 | 2012-02-02 | The Swatch Group Research And Development Ltd | Reduced-contact or contactless force transmission in a clock movement |
US20150131413A1 (en) * | 2013-11-13 | 2015-05-14 | Eta Sa Manufacture Horlogere Suisse | Timepiece comprising a decoupling between the energy transmission means and the counting means |
US20160004223A1 (en) * | 2013-04-10 | 2016-01-07 | The Swatch Group Research And Development Ltd | Winding device for self-winding automatic watch |
US20160070235A1 (en) * | 2013-08-05 | 2016-03-10 | The Swatch Group Research And Development Ltd. | Regulating system for a mechanical watch |
WO2015096975A3 (en) * | 2013-12-23 | 2016-04-21 | Nivarox-Far S.A. | Secure optimized escapement |
EP2894522A3 (en) * | 2013-12-23 | 2016-08-31 | Nivarox-FAR S.A. | Optimised escapement with security system |
CN106062643A (en) * | 2013-12-23 | 2016-10-26 | 尼瓦洛克斯-法尔股份有限公司 | Secure optimized escapement |
JP2017500573A (en) * | 2013-12-23 | 2017-01-05 | ニヴァロックス−ファー ソシエテ アノニム | Optimized escapement with safety means |
US20170123379A1 (en) * | 2014-09-25 | 2017-05-04 | The Swatch Group Research And Development Ltd | Interaction between two timepiece components |
US10958191B2 (en) | 2018-02-15 | 2021-03-23 | The Charles Stark Draper Laboratory, Inc. | Electrostatic motor |
US20220069690A1 (en) * | 2020-08-29 | 2022-03-03 | David Deak, SR. | Inline actuated horizontal pendulum energy harvesting generator and battery-free wireless remote switching system |
-
1970
- 1970-07-30 US US59653A patent/US3652955A/en not_active Expired - Lifetime
Cited By (34)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3769531A (en) * | 1968-10-08 | 1973-10-30 | Proctor Ets | Electrostatic system for generating periodical mechanical vibrations |
US3961209A (en) * | 1972-07-20 | 1976-06-01 | Biviator S.A. | Oscillator for time measurement |
US4189699A (en) * | 1977-04-08 | 1980-02-19 | Mfe Corporation | Limited-rotation motor with integral displacement transducer |
USRE31062E (en) * | 1977-04-08 | 1982-10-19 | Mfe Corporation | Limited-rotation motor with integral displacement transducer |
US4224557A (en) * | 1977-07-13 | 1980-09-23 | Displaytek Corporation Of Sanko | Controlling unit for A.C. driving an electrostatic device |
US4507623A (en) * | 1981-11-20 | 1985-03-26 | Siemens-Albis Ag | Oscillating device with capacitive displacement pickup |
US4694235A (en) * | 1986-08-01 | 1987-09-15 | General Scanning, Inc. | Capacitive position sensor |
US5206448A (en) * | 1990-01-16 | 1993-04-27 | Yamaha Corporation | Musical tone generation device for synthesizing wind or string instruments |
US20030217637A1 (en) * | 2002-05-24 | 2003-11-27 | Shigeru Muramatsu | Performance apparatus |
US6723911B2 (en) * | 2002-05-24 | 2004-04-20 | Yamaha Corporation | Performance apparatus |
US20060114541A1 (en) * | 2002-12-10 | 2006-06-01 | Van Beek Josef T M | Transducer and electronic device |
US7382205B2 (en) * | 2002-12-10 | 2008-06-03 | Nxp B.V. | Transducer and electronic device |
WO2012013374A1 (en) * | 2010-07-30 | 2012-02-02 | The Swatch Group Research And Development Ltd | Reduced-contact or contactless force transmission in a clock movement |
CN103097968A (en) * | 2010-07-30 | 2013-05-08 | 斯沃奇集团研究和开发有限公司 | Reduced-contact or contactless force transmission in a clock movement |
US20130170330A1 (en) * | 2010-07-30 | 2013-07-04 | The Swatch Group Research And Development Ltd | Controlled contact or contactless force transmission in a timepiece |
CN103097968B (en) * | 2010-07-30 | 2015-05-06 | 斯沃奇集团研究和开发有限公司 | Reduced-contact or contactless force transmission in a clock movement |
US9836027B2 (en) * | 2013-04-10 | 2017-12-05 | The Swatch Group Research And Development Ltd | Winding device for self-winding automatic watch |
US20160004223A1 (en) * | 2013-04-10 | 2016-01-07 | The Swatch Group Research And Development Ltd | Winding device for self-winding automatic watch |
US10222757B2 (en) * | 2013-08-05 | 2019-03-05 | The Swatch Group Research And Development Ltd | Regulating system for a mechanical watch |
US20160070235A1 (en) * | 2013-08-05 | 2016-03-10 | The Swatch Group Research And Development Ltd. | Regulating system for a mechanical watch |
US20150131413A1 (en) * | 2013-11-13 | 2015-05-14 | Eta Sa Manufacture Horlogere Suisse | Timepiece comprising a decoupling between the energy transmission means and the counting means |
CN104635469A (en) * | 2013-11-13 | 2015-05-20 | Eta瑞士钟表制造股份有限公司 | Timepiece comprising a decoupling between the means for transmitting power and the counting means |
CN106062643A (en) * | 2013-12-23 | 2016-10-26 | 尼瓦洛克斯-法尔股份有限公司 | Secure optimized escapement |
JP2017500573A (en) * | 2013-12-23 | 2017-01-05 | ニヴァロックス−ファー ソシエテ アノニム | Optimized escapement with safety means |
EP2894522A3 (en) * | 2013-12-23 | 2016-08-31 | Nivarox-FAR S.A. | Optimised escapement with security system |
US9665067B2 (en) | 2013-12-23 | 2017-05-30 | Nivarox-Far S.A. | Optimised escapement with security means |
WO2015096975A3 (en) * | 2013-12-23 | 2016-04-21 | Nivarox-Far S.A. | Secure optimized escapement |
CN106062643B (en) * | 2013-12-23 | 2018-09-25 | 尼瓦洛克斯-法尔股份有限公司 | Has fool proof optimization escapement |
US20170123379A1 (en) * | 2014-09-25 | 2017-05-04 | The Swatch Group Research And Development Ltd | Interaction between two timepiece components |
US10459406B2 (en) * | 2014-09-25 | 2019-10-29 | The Swatch Group Research And Development Ltd | Interaction between two timepiece components |
US10958191B2 (en) | 2018-02-15 | 2021-03-23 | The Charles Stark Draper Laboratory, Inc. | Electrostatic motor |
US11863086B2 (en) | 2018-02-15 | 2024-01-02 | The Charles Stark Draper Laboratory, Inc. | Electrostatic motor |
US20220069690A1 (en) * | 2020-08-29 | 2022-03-03 | David Deak, SR. | Inline actuated horizontal pendulum energy harvesting generator and battery-free wireless remote switching system |
US11855505B2 (en) * | 2020-08-29 | 2023-12-26 | David Deak, SR. | Inline actuated horizontal pendulum energy harvesting generator and battery-free wireless remote switching system |
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Owner name: GENERAL TIME CORPORATION, NORCROSS, GA A CORP. OF Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:MARINE MIDLAND BUSINESS LOANS, INC., A CORP. OF DE;REEL/FRAME:005665/0004 Effective date: 19901105 |