Source: http://www.google.de/patents/US5068653
Timestamp: 2013-06-19 06:03:01
Document Index: 208934850

Matched Legal Cases: ['art 1', 'art 2', 'art 2', 'art 1', 'art 1', 'art 1', 'art 1', 'art 2', 'art 2', 'art 2']

Patent US5068653 - Capacitive displacement measuring device with t-shaped scale coatings - Google PatenteSuche Bilder Maps Play YouTube News Gmail Drive Mehr » Erweiterte Patentsuche | Webprotokoll | Anmelden Erweiterte Patentsuche PatenteA capacitance length and/or angle measuring device has a transducer comprising a stationary part (1) forming a scale and a part (2) displaceable parallel over the surface of the scale, at a short distance therefrom and acting as a sensing unit. The opposite surfaces of the scale and sensing unit are...http://www.google.de/patents/US5068653?utm_source=gb-gplus-sharePatent US5068653 - Capacitive displacement measuring device with t-shaped scale coatings Ver�ffentlichungsnummerUS5068653 APublikationstypErteilung Anmeldenummer06/670,349 Ver�ffentlichungsdatum26. Nov. 1991Eingetragen9. Nov. 1984 Priorit�tsdatum11. Nov. 1983Auch ver�ffentlicht unterDE3340782A1, DE3340782C2, EP0184584A2, EP0184584A3, EP0184584B1 Ver�ffentlichungsnummer06670349, 670349, US 5068653 A, US 5068653A, US-A-5068653, US5068653 A, US5068653A ErfinderSiegfried Gruhler, Otto Klingler, Helmut RiviniusUrspr�nglich Bevollm�chtigterMauser-Werke Oberndorf GmbhPatentzitate (12), Referenziert von (12), Klassifizierungen (15) Externe Links: USPTO, USPTO-Zuordnung, EspacenetCapacitive displacement measuring device with t-shaped scale coatingsUS 5068653 A Zusammenfassung A capacitance length and/or angle measuring device has a transducer comprising a stationary part (1) forming a scale and a part (2) displaceable parallel over the surface of the scale, at a short distance therefrom and acting as a sensing unit. The opposite surfaces of the scale and sensing unit are provided with capacitor coatings (5,6,7,8,9). The mechanical quantity to be measured causes an area vibration of a capacitor, the capacitance variation resulting therefrom acting as a variable capacitive reactance in a circuit, which changes the phase position of the electrical signals. With an appropriate configuration of the capacitor surfaces one obtains a linear function between the mechanical quantity to be measured and the phase portion of the signals.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, the transducer for a length and angle measuring device according to the invention comprises a stationary part 1, which forms the scale, and the displaceable part 2, which constitutes the sensing unit. The displaceable part 2 is mounted at a short distance above the stationary part 1 and is displaceable parallel thereto. The opposite surfaces 3 and 4 are provided with capacitor coatings 5,6,7,8 and 9. The coatings 5 and 6 of the stationary part 1 are T-shaped and applied on part 1 in such a way that there result two rows of coatings which interengage in comb fashion. The coatings 5 and 6 of the stationary part 1, or respectively of the scale, are not connected electrically. They are sensed contactlessly by the displaceable part 2. The capacitor coatings 7 (7.1 to 7.3) of the displaceable part 2 of the transducer are formed as rectangular coatings and arranged symmetrically on part 2 in direct juxtaposition. They function as transmitting electrodes. At an angle of 90 the coatings 7 are the capacitor coatings 8 and 9, which function as receiving electrodes. As can be seen from FIG. 2, the receiving electrodes 8 and 9 extend over the entire arrangement of the transmitting electrodes 7.
The symmetrical arrangement of the coatings 7, 8, 9 of the sensing unit 2 with respect to the displacement axis 14 and the amplification axis 14 and the amplification of the two received signals phase-shifted by 180 by means of differential amplifier bring about a doubling of the signal and an extensive compensation of the error signals that may be caused by tilting about the displacement axis 14.
The coatings 7.1, 7.2, 7.3 of each transmitting group 11 are powered with three sinusoidal A.C. voltages at 15.1, 15.2 and 15.3 of equal amplitude and equal frequency, phase-shifted by 120
15.1=15.1.times.sin (wt)
15.2=15.2.times.sin (wt+120
15.3-15.3.times.sin (wt+240
17.1=17.1.times.sin (wt+18.1)
17.2=17.2.times.sin (wt+18.2)
18.1=18.2+180
The displacement position X corresponds to the transducer position shown in FIG. 3. The partial capacitances 16.1, 16.2 and 16.3 appear as a function of the displacement path 19. Here a purely sinusoidal response of the partial capacitances would be ideal, as it would lead to a constant amplitude response of the receiver voltage 17.1. To achieve this, however, a complicated geometry of the capacitor coatings would be required. With the displacement of the sensing unit 2 by one scale period 1, corresponding to the value 12 in FIG. 1 or 11 in FIG. 2, there results a phase shift of φ 18.1 by 360 mm, in the configuration of the transducer according to FIGS. 1 and 2, upon displacement by one scale period T the phase angle error of the receiver voltages is .+-.1.1 of the displacement 19 of .+-0092 mm. This phase angle error is largely compensated by the linking of the two received signals 17.1 and 17.2 in the electronic circuit system.
The capacitive transducer is included in a digital system. Power supply to the transducer occurs with three A.C. voltages phase-shifted by 120 transmitting voltage generating unit 20 by known methods from square signals. Feeding with digital signals which contain only harmonics of higher order is, of course, possible also. Such harmonics are indeed transmitted into the output signal of the transducer, but they can be eliminated with a filter 21 connected ahead of the zero crossing detector 22. Thereby a square receiver signal is produced, whose phase position relative to the digital reference signal of equal frequency, which is generated in the reference divider 23, contains the data of the mechanical quantity to be measured. The phase evaluation takes place in a control circuit, in that the reference signal is continuously synchronized with the receiver signal in the synchronization stage 25. By a phase comparison 24 of the two signals a pulse is generated whose width is proportional to the phase shift. Firstly, this pulse controls the synchronization stage 25, which by mixing in or blanking out of pulses synchronizes the reference divider 23 to the receiver signal. This means that the phase shift is controlled to zero. Secondly, the pulse generated in the phase comparator 24 controls a gate 26 for a clock frequency of a counter 27. The entire system is controlled by a clock pulse supplied by a crystal-stabilized oscillator 28.
Patentzitate Zitiertes PatentEingetragen Ver�ffentlichungsdatum Antragsteller TitelUS3146394 *20. Apr. 196025. Aug. 1964Continental Elektroindustrie A. G.Apparatus for proportionally converting a rotational angle into a phase angle of an alternating voltageUS3221256 *15. Mai 196330. Nov. 1965Whittaker CorporationElectrostatic position transducerUS3348133 *18. Okt. 196517. Okt. 1967Sogenique (Electronics) LimitedPosition responsive apparatus including a capacitive potentiometerUS3845377 *13. Apr. 197329. Okt. 1974Nihon Regulator Co Ltd,JaRotational angle transducerUS3961318 *17. Jan. 19751. Juni 1976Inductosyn CorporationElectrostatic position-measuring transducerUS4223300 *16. Febr. 197816. Sept. 1980Aga AktiebolagElectro mechanical position indicator using relatively moveable coilsUS4242666 *23. Mai 197930. Dez. 1980General Electric CompanyRange selectable contactless data acquisition system for rotating machineryUS4339709 *3. Apr. 198013. Juli 1982FacomDevice for measuring the relative position of two objectsUS4562430 *20. Dez. 198231. Dez. 1985Agence Spatiale EuropeennePosition detection device for magnetic bearingUS4573048 *8. Mai 198525. Febr. 1986Dash Strauss AssociatesHigh speed link for rotating displayCH539837A * Titel nicht verf�gbarDE2853142A1 *8. Dez. 197821. Juni 1979Stiftelsen Institutet Foer Mikrovaagsteknik Vid Tekniska HoegskolanMessvorrichtung zur kapazitiven bestimmung der relativen lagen zweier zueinander beweglicher teile* Vom Pr�fer zitiert Referenziert von Zitiert von PatentEingetragen Ver�ffentlichungsdatum Antragsteller TitelUS5304937 *4. Sept. 199219. Apr. 1994Meyer; Hans U.Capacitive position sensor with an electrode array cursor and topographically featured scaleUS5347848 *15. Jan. 199320. Sept. 1994Robert Bosch GmbhApparatus for measuring a hydraulic fluid flow rate and/or leakage rate through an object to be testedUS5394096 *16. Nov. 199328. Febr. 1995Meyer; Hans U.Capacitive position sensor including a scale with integral topographical features which effect the mutual capacitance between cursor electrodesUS5534859 *23. Sept. 19949. Juli 1996Meyer; Hans U.Instrument for measuring lengths or anglesUS5828142 *22. Aug. 199727. Okt. 1998Mrs Technology, Inc.Platen for use with lithographic stages and method of making sameUS5977781 *5. Juni 19962. Nov. 1999Brown & Sharpe Tesa S.A.Capacitive measuring deviceUS6031380 *5. Dez. 199629. Febr. 2000Horst Siedle Gmbh & Co. Kg.Method and device for determining the respective geometrical position of a body by capacitive sensingUS6133743 *7. Mai 199817. Okt. 2000Horst Siedle Gmbh & Co. KgMethod and device for determining the respective geometrical position of a body by capactive sensingUS6492820 *26. Dez. 200010. Dez. 2002Mitutoyo CorporationDisplacement measuring deviceUS6538457 *18. Jan. 200125. M�rz 2003Mitutoyo CorporationCapacitance type displacement detection apparatus and method of manufacturing the sameUS659375712. Nov. 200215. Juli 2003Mitutoyo CorporationCapacitance type displacement detection apparatusUS81078787. Nov. 200731. Jan. 2012Motorola Mobility, Inc.Methods and apparatus for user-selectable programmable housing skin sensors for user mode optimization and control* Vom Pr�fer zitiertKlassifizierungen US-Klassifikation340/870.37, 324/161, 324/659Internationale KlassifikationG01D5/24, G01D5/241, G01B7/02, G01B7/30, G01D5/12, G01B7/00 UnternehmensklassifikationG01B7/02, G01D5/2415, G01B7/30 Europ�ische KlassifikationG01B7/02, G01B7/30, G01D5/241B1DrehenOriginalbildGoogle-Startseite - Sitemap - USPTO-Bulk-Downloads - Datenschutzerkl�rung - Nutzungsbedingungen - �ber Google Patente - Feedback gebenDaten bereitgestellt von IFI CLAIMS Patent Services.© 2012 Google