| 摘要 |
696,741. Piezo-electric instruments. PHILIPS ELECTRICAL INDUSTRIES, Ltd. Jan. 23, 1952 [Jan. 26, 1951], No. 1875/52. Class 40 (iv). [Also in Groups XXIII and XL (c)] In a piezo-electric oscillator arrangement comprising an amplifier 9 and a tubular body 1 of polarized, polycrystalline dielectric material, e.g. sintered barium titanate, having an inner electrode 3 and outer driving and feed-back electrodes 4 and 5 respectively, the body 1 is made to oscillate along its length by adjusting the phase relationship of the feed-back relative to the driving potential and is used to generate audio or supersonic energy or to drive a percussion drilling tool 8. The phase relationship between electrodes 4 and 5 is adjusted by a potentiometer 13 in series with a condenser 12. The body may oscillate at its natural frequency or at a harmonic thereof and in the latter case additional outer electrodes are required. The additional electrode may be supplied with an out-of-phase potential or the sections of the tube under the electrodes may be polarized in opposite directions. A suitable coupling head for transmitting supersonic energy to a medium is described with reference to Fig. 2 (not shown). |
