| 摘要 |
A stethoscope head having a first pair of acoustical passages in sound communication with a low frequency sound receiving bell and a second pair of acoustical passages in sound communication with a high frequency sound receiving diaphragm. A cylindrical valve plug having a third pair of acoustical passages is disposed within a cylindrical bore into which the first and second pairs of acoustical passages open. A pair of sound tubes are connected to the third acoustical passages within the cylindrical valve plug. The pair of sound tubes act as a lever to facilitate rotation of the cylindrical valve plug to acoustically connect the third acoustical passages with either the first or second pair of acoustical passages.
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