Stethoscope with reduced susceptibility to interference from ambient noise
First Claim
1. A stethoscope chestpiece for transducing skin vibrations due to internal physiologic processes of a patient with an increased signal to noise ratio, comprising:
- a first air cavity adapted to be coupled to skin;
diaphragm means with a front side and a rear side, in which the front side of the diaphragm means is coupled to the first air cavity, and the rear side of the diaphragm means is coupled to free air, where the diaphragm means is set back from the patient'"'"'s skin so that there is no direct physical contact between the front side of the diaphragm means and the patient'"'"'s skin, so that the only forces available to act on the diaphragm means are due to the air pressure present at the front and rear sides of the diaphragm means, and;
transducer means coupled to the diaphragm means, wherein the transducer means outputs a signal in response to the vibration of the diaphragm means, where the vibration of the diaphragm means is due to the air pressure difference between the front and rear sides of the diaphragm means.
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Abstract
A stethoscope, and a stethoscope chestpiece, with an increased signal to noise ratio. The invention concerns mechanical improvements to both traditional mechano-acoustic stethoscopes, and to electronic stethoscopes. The stethoscope chestpieces of this invention are constructed so that the transducers are responsive to the pressure differences between air pressure variations in the chestpiece air cavity which is coupled to the skin, and the air pressure variation due to ambient noise present in the environment. The result is a transducer output with increased signal to noise ratio.
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Citations
43 Claims
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1. A stethoscope chestpiece for transducing skin vibrations due to internal physiologic processes of a patient with an increased signal to noise ratio, comprising:
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a first air cavity adapted to be coupled to skin; diaphragm means with a front side and a rear side, in which the front side of the diaphragm means is coupled to the first air cavity, and the rear side of the diaphragm means is coupled to free air, where the diaphragm means is set back from the patient'"'"'s skin so that there is no direct physical contact between the front side of the diaphragm means and the patient'"'"'s skin, so that the only forces available to act on the diaphragm means are due to the air pressure present at the front and rear sides of the diaphragm means, and; transducer means coupled to the diaphragm means, wherein the transducer means outputs a signal in response to the vibration of the diaphragm means, where the vibration of the diaphragm means is due to the air pressure difference between the front and rear sides of the diaphragm means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A stethoscope chestpiece for transducing skin vibrations due to internal physiologic processes of a patient with an increased signal to noise ratio, comprising:
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a first air cavity adapted to be coupled to the skin; an acoustical mass coupled to free air; an acoustical resistance coupled to free air; a second air cavity coupled to both the acoustical mass and the acoustical resistance; diaphragm means with a front side and a rear side, in which the front side of the diaphragm means is coupled to the first air cavity, and the rear side of the diaphragm means is coupled to the second air cavity, where the diaphragm means is set back from the patient'"'"'s skin so that there is no direct physical contact between the front side of the diaphragm means and the patient'"'"'s skin, so that the only forces available to act on the diaphragm means are due to the air pressure present at the front and rear sides of the diaphragm means, and; transducer means coupled to the diaphragm means, wherein the transducer means outputs a signal in response to the vibration of the diaphragm means, where the vibration of the diaphragm means is due to the air pressure difference between the front and rear sides of the diaphragm means. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A stethoscope for transducing skin vibrations due to internal physiologic processes of a patient with an increased signal to noise ratio in the presence of ambient noise, comprising:
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a chestpiece including; a first air cavity adapted to be coupled to the skin; a first diaphragm means with a front side and a rear side, where the front side of the first diaphragm means is coupled to the first air cavity and set back from the patient'"'"'s skin so that no portion of the diaphragm means comes in direct physical contact with the patient'"'"'s skin, so that the only forces available to act on the diaphragm means are due to the air pressure present at the front and rear sides of the diaphragm means; and transducer means coupled to the diaphragm means, wherein the transducer means outputs a signal in response to the vibration of the diaphragm means, where the vibration of the diaphragm means is due to the air pressure difference between the front and rear sides of the diaphragm means, and; means for presenting the transducer means output signal to the user'"'"'s ears. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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31. A stethoscope chestpiece for transducing skin vibrations with an increased signal to noise ratio, comprising:
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a first air cavity adapted to be coupled to the skin; a second air cavity; a first diaphragm means with a front side and a rear side, where the front side of first diaphragm means is coupled to the second air cavity, and the rear side of first diaphragm means is coupled to free air; and transducer means coupled to the first and second air cavities, and not directly coupled to the patient'"'"'s skin, wherein the transducer means outputs a signal in response to the pressure difference between the air pressure within the first air cavity and the air pressure within the second air cavity. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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Specification