Method of and apparatus for detecting damage to a frangible object
Patent 4072936 Issued on February 7, 1978. Estimated Expiration Date: 
February 7, 1995. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
February 7, 1995. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3618062 3863250 3889250 InventorApplicationNo. 05/767941 filed on 02/11/1977US Classes:340/566, Vibration310/319, Electrical output circuit310/323.21, Detector (e.g., sensor)310/366More than twoExaminersPrimary: Swann, III, Glen R.Attorney, Agent or FirmForeign Application Priority Data1976-09-09 CHAbstractDamage to a frangible article, particularly a glass window is detected by sensors responsive to oscillations in different frequency bands. Only when all the sensors are simultaneously responsive is an alarm signal, denotive of damage to the article, developed. Piezo-ceramic transducers respond to frequencies within the range of 30 kHz to 1 MHz. The sensors are connected in parallel with inductors to provide resonant amplification of the voltage developed. The resultant signals are amplified and applied to an AND gate yielding the required output signal. | |
