Mechanically operable acoustic filter
Patent 4167223 Issued on September 11, 1979. Estimated Expiration Date: 
June 19, 1998. 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.
June 19, 1998. 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 585525 1429664 1994008 2792902 3690404 InventorApplicationNo. 05/916840 filed on 06/19/1978US Classes:181/131, Stethoscope381/354, Absorbing or attenuating element381/67STETHOSCOPES, ELECTRICALExaminersPrimary: Tomsky, Stephen J.Attorney, Agent or FirmInternational ClassesA61B 7/02 (20060101)A61B 7/00 (20060101) G10K 11/04 (20060101) G10K 13/00 (20060101) H04R 1/22 (20060101) G10K 11/00 (20060101) Foreign Application Priority Data1977-06-27 FRAbstractA mechanically operable acoustic filter for varying the acoustic spectrum of transmitted sound signals. Sound signals, e.g. from a patient's skin when the filter is incorporated into the chest piece of a stethoscope, are received at an inlet orifice which may or may not be provided with an outer diaphragm. A thin, preferably Mylar filtering diaphragm partitions the interior of the chest piece into two chambers communicating with respective inlet and outlet orifices and each other through a central opening in the filtering diaphragm in line with a central passageway in a tensioning member for the filtering diaphragm. The position of the tensioning member is adjustable by a knob disposed outside the chest piece between a first position in which all frequencies pass by way of the central opening and successive positions in which the diaphragm is correspondingly tensioned at the same time the free vibrating area thereof is reduced. | |
