| 摘要 |
665,100. Piezo-electric instruments. BRUSH DEVELOPMENT CO. Oct. 22, 1947 [Nov. 30, 1946], No. 28242/47. Class 40 (iv). [Also in Group XL (b)] A piezo-electric instrument is made by fixing one end of a crystal element to a flat rigid base and working the free end of the crystal until it is parallel to the base or level with the adjacent end of the housing of the instrument. As shown, the crystals 33 are arranged in two rings and when affixed to the base project above the rim 34 of the cup-shaped housing. The projecting portions are then ground until they are level with the rim and a diaphragm 41 is cemented to the levelled surface and secured to the rim by a sealing ring 42. Electrodes 35 and 36 of the crystals are connected by leads 37 and 38. The Specification as open to inspection under Sect. 91 also includes the subject-matter of Specifications 665,189 and 665,190. [Group XL (b)]. This subject-matter does not appear in the Specification as accepted. |
