| 摘要 |
1,108,846. Piezo electric transducers. KISTLER INSTRUMENTE A. G. Dec. 1, 1965 [Dec. 10, 1964], No. 50965/65. Heading G1N. A force sensitive transducer consists of a stack of apertured Piezo electric discs, each of which 35, Fig. 4, generates a voltage between its plane surfaces when stressed and has metal electrodes 39, 40 deposited or coated thereon, adjacent discs being arranged so that contacting electrodes have the same polarity as one another. Each disc has at least one aperture which may be central, and the electrodes 39, 40 are respectively connected to annular metal deposits 37, 43 on the opposite face, by means of metal coatings on the wall 41 of the aperture, and on the periphery, 44 of the disc. The electrodes on each disc are insulated from one another by non- coated annular portions 38, 42. In a stack of such plates, Fig. 5 (not shown), the coatings on the walls of the apertures link together to connect the positive electrodes to a terminal (54) in an insulating cylinder (53) of ceramic, set in a conductive end-plate (52); and the negative electrodes are connected via the peripheral coatings (44) to the end-plate (52). The end-plate (52) alternatively may be insulating, and carry a coating (57) of for example gold, on its outer curved surface. Each disc, alternatively, may have two coated apertures Fig. 3 (not shown) serving as positive and negative terminals respectively, insulating non-coated annuli (6) again being provided to isolate the electrodes. The discs of the stack are held together by high vacuum welding, or by being pre-stressed and coated with silicon varnish, the discs being arranged with their axes of minimum thermal expansion coefficient in alignment. In a further refinement Fig. 8 (not shown) the end-discs (66, 67) each have the metal coatings on opposite faces joined together via the peripheral coating. Figs. 10, 11 (not shown) to short circuit their own outputs. These discs then serve to absorb any difference in thermal expansion between the remaining stack of discs and the end members (68, 69) to reduce temperature induced stresses in the discs. In a pressure measuring transducer, Fig. 12 (not shown) a stack of discs is sealed in a housing, (92) with the end-plate (90) bearing against a gold plated diaphragm (91) the housing itself forming one terminal, and a central aperture (94) the other terminal.
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