Resonant chamber sound pick-up

• US 6,587,564 B1
• Filed: 05/25/1999
• Issued: 07/01/2003
• Est. Priority Date: 05/25/1999
• Status: Expired due to Fees

• Current Assignee: Frank A. Bilan
• Original Assignee: Cusson, Ronald Y.
• Inventors: Cusson, Ronald Y.
• Primary Examiner(s): Isen, Forester W.
• Assistant Examiner(s): MCCHESNEY, ELIZABETH A
• Application Number:
  US09/318,250
• Time in Patent Office: 1,498 Days
• Field of Search: 381/67, 381/92, 181/131
• US Class Current: 381/67
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• CPC Class Codes: H04R 1/46 Special adaptations for use as contact microphones, e.g. on musical instrument, on stethoscope throat mountings H04R1/14

Abstract

A noise-reducing resonant chamber sound pick-up for electronic stethoscopes is claimed. It consists of a resonating chamber (24) which acoustically preamplifies the selected frequencies of heart sounds, 50-150 hz, and bruits of breath or blood, 150-500 hz, while rejecting ambient sounds. A skin contact (34) has elastic foam support (14), whose rigidity is varied by varying the applied pressure, in order to select the preamplified band of sounds. The other side of the resonating chamber contains a sound transducer (10) largely encased in heavy malleable metal (12) that absorbs sound not coming from the chamber. A damping vent hole (26) shapes the band of preamplified sounds. The resulting superior signal-to-noise ratio permits two, small chambers to be used in a stereophonic chest piece little larger than that of a conventional stethoscope, with better amplification enabling examination through clothing or surgical dressing even in heavy persons.

Claims

1. A resonant chamber sound pick-up comprising:

(a) a sound pick-up element rigidly encased in a heavy malleable metal ballast, except for the chamber face, with the active face of the sound pick-up flush with the front face of the ballast,

(b) an elastic closed-cell foam shield largely surrounding the ballast so as to allow it to vibrate to sound in the resonant chamber formed by the extension of this foam shield and of,

(c) a diaphragm supported by the foam extension, whereby said resonance chamber selectively amplifies sound frequencies determined by the mass of the ballast and the foam elasticity, while rejecting ambient sound.