John C Devine

US Patent:

40139905, Mar 22, 1977

Filed:

Jun 30, 1975

Appl. No.:

5/591268

Inventors:

John A. Devine - Granada Hills CA

Assignee:

The Bendix Corporation - North Hollywood CA

International Classification:

H04R 122
H04R 144

US Classification:

340 3T

Abstract:

An airborne sonar system includes a transducer with both projecting elements and receiving elements designed for echo ranging at a moderately high frequency. Carried on the transducer housing is an additional hydrophone which is sensitive to sonar input signals at low frequency and, hence, which has a capability of responding to signals from much longer range than can the receiving elements of the echo ranging transducer. This low frequency hydrophone is sensitive to the frequency of much of the noise and vibration imparted to the transducer housing by the supporting aircraft and so, in operation, the hydrophone is suspended on a very compliant mounting consisting of a plurality of strips of light rubber tubing. To avoid damaging the hydrophone or the mounting structure, a water pressure responsive bellows is positioned adjacent to the hydrophone so that when the combined assembly is carried in air or being deployed or retrieved from the water, the bellows is expanded and serves to cage or secure the hydrophone by pressing it against part of the transducer structure. When the transducer is deployed at the desired depth in the water, the bellows is collapsed, freeing the hydrophone and leaving it suspended on the very light tubing members which serve to damp out the noise from the cable and housing.