Abstract: The disclosed flextensor transducer enables the transmission and reception of acoustic waves in water at very great depths. It includes at least one pillar of piezoelectrical cells placed within an impervious shell. Each pillar is supported solely by a first end on the shell, and is compressed on the shell by a counter-mass applied to its second end.

Abstract: A Tonpilz type piezoelectric transducer which can be used alternately as a wide-band receiver and an emitter includes a stack of pairs of piezoelectric segments separated by electrodes, the stack being placed between a horn and a countermass. An emitter is connected by a conductor to one of the two electrodes for each segment pair. One pair of segments next to the countermass is separated from the others by an insulator. The two electrodes to either side of the one pair are connected in parallel to a receiver and, through two diodes connected in opposition, to a grounded common conductor.

Abstract: An electro-acoustic transducer according to the invention is of the Tonpilz type comprising a stack of piezo-electric plates placed between a horn and a countermass, and electrodes inserted between the plates. Some of the electrodes are connected to a common excitation or output conductor through phase-shifting circuits which allow the electric voltage of a proportion of these electrodes to be dephased. A logic unit allows the phase-shifting of the electrodes to be distributed within the stack according to several different groupings in dependence upon frequency. One application of the invention is to the construction of long-range power sonars.

Abstract: A new piezoelectric transducer incorporated with a mechanical amplifier is described. The transducer comprises a rigid base plate; two lateral plates whose lower edge is connected to the plate by a thin portion; a stack of piezoelectric elements having alternate electrodes; a horn formed of a flexible elastic diaphragm which connects together the upper edges of the two plates; an enclosure and a sealing skin which is acoustically transparent. The tranducer is capable of emitting or receiving high power acoustic waves of very low frequencies including for instance, a few Hertz to 500 Hz.

Abstract: An underwater acoustic reflector and method for making an acoustic underwater reflector is described herein whereby electrodes are immersed in an aqueous electrolyte solution and thereafter connected to a supply of electrical current. The electrodes are selected such that bubbles form on at least one of the electrodes, providing a layer of acoustic reflective bubbles. Control of the reflectivity properties according to the intensity of the electrolyzing current is also described.

Abstract: Piezoelectric transducers and antennas comprising a plurality of identical transducers arranged coaxially, each transducer comprising a ring and a plurality of piezoelectric motor elements arranged radially against the inner wall of the ring. The rings form an envelope which is closed by two covers and the envelope encloses an axial cylindrical channel containing a piston. The inside of the envelope contains a solid material which is elastomeric or rigid and is separated from the inner walls of the envelope by a small clearance which communicates with the end of the cylinder. An application is the construction of acoustic antennas intended to be immersed to great depths.

Abstract: A piezoelectric transducer adapted to be immersed in water at great depths, and suitable for applications as a sonar antenna, comprising a cylindrical envelope, a number of piezoelectric drivers disposed within the envelope and constituted by at least one stack of elements alternating with electrodes, at least one pre-stressing rod for interconnecting and compressing the stack, and a common intermediate member to which the drivers are secured by the rod, the member also acting as a counter-mass for the drivers.

Abstract: A piezo-electric transducer for low frequency acoustical waves comprising a stack of piezo-electric elements and alternating electrodes disposed between a front receiver plate and a counter mass. The countermass comprises a rigid annular block surrounding the stack, a rear plate engaging the rear of the stack and an elastic connection between the block and the rear plate.