US 3264585 A
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Description (OCR text may contain errors)
Aug. 2, 1966 w. POSCHENRIEDER 3,264,585
DUAL ELECTROSTRICTIVE DRIVERS BONDED TO AND DRIVING OPPOSITE SIDES 0F MECHANICAL RESONATOR Filed June 5, 1962 United States Patent DUAL ELECTROSTRICTIVE DRIVERS BONDED TO AND DRIVING OPPOSETE SIDES OF MECHANI- CAL RESONATOR Werner Poschenrieder, Munich, Germany, assignor to Siemens & Halske Aktiengesellschaft, Berlin and Mnnich, Germany, a corporation of Germany Filed .Tune 5, 1962, Ser. No. 200,255
Claims priority, application Germany, June 20, 1961,
2 Claims. (a. 333-72 The invention disclosed herein is concerned with an electrostrictive coupling arrangement for a resonator performing oscillations according to the longitudinal mode, such resonator being made preponderantly of material which is inactive in electrostrictive sense, especially of a metal, preferably steel, the remaining resonator parts being made of electrostrictive material, especially ceramic material which is active in electrostrictive sense and provided with energizing or triggering electrodes.
Coupling arrangements of this general kind, for longitudinal oscillators, are described in the copending application Serial No. 91,215, filed February 23, 1961, owned by the assignee also named in the present case.
The object of the present invention is to improve the prior structure by forming the resonator as a fiat strip made of material which is inactive in electrostrictive sense, such strip being inthe region of the zone which is neutral for longitudinal oscillations, provided on both sides thereof with flat layers of electrostrictive material covering preferably only part of the resonator length, and disposing upon each side of the respective layers, which faces away from the resonator, an energizing or triggering electrode serving for feeding in identical phase the parts which are active in electrostrictive sense with respect to the resonator proper.
Details of the invention will appear from the description which is rendered below with reference to the accompanying drawing showing an embodiment thereof.
The drawing shows an electromechanical filter comprising three longitudinal oscillators 1, 2 and 3. These longitudinal oscillators which are of flat configuration, are interconnected by coupling bridges in the manner described in the previously noted copending application.
The coupling arrangement according to the present invention is provided respectively at the input and the output sides of the filter formed by the longitudinal oscillators. It comprises two thin plates 4, 5 of electrostrictive ceramic material which are soldered to the respective longitudinal oscillators 1 and 3, made preferably of steel, symmetrically with respect to the neutral zone thereof which is indicated by a dot-dash line. The sides of the plates 4 and 5, made of electrostrictive material, which face away from the steel resonator, are metallized. Each metallized side is provided with a lead-in wire such as indicated at 6 and 7, which extends therefrom preferably in the region of the neutral zone. A further leading wire 8 extends from the respective longitudinal oscillators,
Patented August 2, 1966 "ice which are made of steel, at points which are suitably likewise placed in the region of the neutral zone. However, the further lead-in wires may also be placed outside of such region.
The respective two lead-in wires 6 and 7, which are mutually interconnected, serve as terminals for the energizing or triggering electrodes of the ceramic plates 4 and 5 with respect to the metallic resonator bodies 1 and 3. Accordingly, there is effected a phased feed for the energizing or triggering devices disposed upon the two sides of the resonator. This results in triggering which is the more positive and definite the more uniform the ceramic parts are which are being used. This will be understood upon considering that the individual ceramic plate will attempt to excite the respective longitudinal oscillator to a bending oscillation which is, however, made impossible due to the fact that the bending components of the two triggering devices of the individual coupling arrangement are mutually cancelled, thus resulting in a pure longitudinal excitation.
The steel body which is made of one piece can of course form more or fewer than three resonators.
Changes may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent.
1. A resonator for executing longitudinal oscillations, comprising a generally fiat strip made of material which is inactive in electrostrictive sense and forms the resonator proper, and an electrostrictive coupling arrangement, comprising a pair of substantially identical flat layers made of electrostrictive material, each of which is disposed at a respective side of said strip in the region of the zone which is neutral for longitudinal oscillations, said layers coextensively covering opposite sides of said strip only for part of its length, each layer being provided with a triggering electrode upon the side thereof which faces away from said strip, and means for utilizing said triggering electrodes for feeding in identical phase the parts which are active in electrostrictive sense with respect to the resonator proper.
2. A resonator according to claim 1, wherein said strip is made of steel, said layers being formed of electrostrictive ceramic material, each layer being metallized on the side thereof which faces away from said strip and which form the respective triggering electrodes.
References Cited by the Examiner UNITED STATES PATENTS 2,695,357 11/1954 Douley 33372 2,814,785 11/1957 Burns 33371 3,015,789 1/1962 Honda 333-71 3,064,213 11/1962 Mason 333-71 3,086,183 4/1963 SChOfer 33372 HERMAN KARL SAALBACH, Primary Examiner.
C. BARAFF, Assistant Examiner.