Abstract: An underwater acoustical projector has its barrel staves located radially tward of a piezoelectric ceramic driver. The barrel staves are in an hour glass arrangement. The cross-sectional arrangement of the barrel staves is circular at both the top and bottom of the hour glass forming elliptical cross-sections of varying eccentricity between said top and bottom of said staves. The cross-section of greatest eccentricity is located midway between the top and bottom of said staves. The cross-section of greatest eccentricity is located midway between the top and bottom of the barrel staves. This forms a projector with a varying radius of curvature in each of the four 90.degree. quadrants around the axis of the projector. This yields large changes in the resonant frequency.

Abstract: An electro-acoustic transducer comprises two transducer units each having first and second ends, a tubular supporting member disposed between the two transducer units, and a pair of oppositely disposed supporting components between which the transducer units and tubular member are disposed. One of the transducer units is compressively clamped between one of the supporting components and one end of the tubular member, and the other of the transducer elements is compressively clamped between the other of the supporting components and the other end of the tubular member.

Abstract: A sonde is secured to the end of an electrical cable and is inserted is a bore hole by means of the electrical cable. The sonde has a transmitter and receiver. The other end of the cable is secured to apparatus on the surface, and the apparatus includes means for forming a signal transmitting it through the cable to the transmitter, the transmitter emitting the signal from the sonde, that signal bouncing off of the wall of the bore hole and then back to the receiver. The signal is then sent from the receiver through the cable to the apparatus on the ground. That apparatus also has means for recording the results of the signals so formed and mainpulated. The transmitter and the receiver in the sonde are placed together, not more than one half of the wave length of the signal, and to a spacing as small as zero, with transmitter and receiver effectively in one location.

Abstract: A direction selective transducer which includes a center mass fixed between two active transducer element stacks and two head masses. The center mass couples the two stacks and allows the ratio of radiation produced by each head mass to be selected as desired by varying the amplitude and phase of drive voltages applied to the stacks. The transducer can also be used as a directional receiver.

Abstract: This electroacoustic transducer has a structure of the so-called "Tonpilz" general type, i.e., comprising a radiating horn, a rear mass and a motor formed by at least one piezoelectric element interposed between said horn and said rear mass, and electrically excited so as to produce a vibration transmitted to the horn. Said piezoelectric element is submitted to an electric field with a direction perpendicular to the main direction of polarization of said piezoelectric material so as to stress the latter in the shear mode.

Abstract: The underwater sound projector includes a hollow-cylindrical metal housing having a recess with an opening. A non-ceramic flexural disc is supported over the opening. Within the recess is a stack of piezoelectric ring elements. A metal drive head transfers force axially from the stack to an annular area on the disc spaced from the center thereof. Foil electrodes are interposed between the piezoelectric rings and situated at the ends of the stack. A stress bolt clamp connects the drive head to the housing with the stack situated therebetween.

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 flextensional sonar transducer assembly includes a stack of piezoelectric elements disposed along a linear axis, a plurality of electrodes disposed between the elements, end pieces disposed at each end of the piezoelectric stack, with the end pieces having outwardly facing, generally arcuate surfaces, a compression band formed into a loop to encircle the stack and end pieces, a flexural shell disposed to circumscribe the compression band to present a generally elliptical side cross-section, with the major axis thereof being generally coincident with the linear axis of the stack, and with the shell being reactively coupled to the arcuate end portions of the compression band, and rod members positioned between the compression band and the arcuate end portions of the band of material for maintaining driving contact between the shell and the end pieces, and for adjusting the prestress compression pressure in the stack. The invention also includes methods of manufacturing the transducer assembly.

Abstract: Electrical signal-receiving transducers for logging tools include a silicon plate having piezoresistors formed thereon and response to deflection caused by pressure waves acting on said plate to generate an electrical signal through a bridge circuit including balancing resistors. Another embodiment of the transducer comprises a curved plate which is supported in a tool cavity for response to a pressure wave to deflect and exert forces on a piezoelectric element to generate a signal proportional to the deflection and a pressure wave causing such deflection. Monopole and quadrupole arrangements of the curved plate may be used for sensing or generating symmetric and asymmetric wave forms.

Abstract: This invention is a multiple segment flextensional transducer shell that is easily and quickly manufactured and modified. The shell may comprise two adjustable, flexible plates and two buttress bars or two J-shaped adjustable, flexible plates. When the buttress bars and plates or the J-shaped members are connected together at or near the nodal points of the transducer, the assembled shell will have the same shape as the flextensional transducer shells used in the prior art. The open ends of the assembled transducer shell are covered with flanges and a boot is placed over the shell and flanges to make the interior of the shell air tight.

Abstract: A flextensional transducer provides a low resonance frequency by having its shell portions connected to its ends by a pin- or rotation-type hinge whereby the motion of the ends of the transducer caused by energization of the transducer drive is transferred to the shell portions by the hinge. The reduction in the resonance frequency is achieved by the shell portions acting as a hinged plate whose ends rotate relative to the transducer ends rather than being cantilevered as in the prior art.

Abstract: An omnidirectional acoustic transducer achieves a broadband radiation or reception pattern with high efficiency by using several transducer rings located side-by-side with each ring comprising a plurality of radially directed individual transducer elements. The transducer elements in each of the rings are tuned to a particular natural frequency and are designed accordingly. Within each ring the transducer elements are energized in phase with one another. The natural frequency of the individual transducer elements differs from one ring to the other.

Abstract: A low frequency sonar transducer comprising a head (1) having first and second stacks of piezo ceramic elements (2,3) in two spaced apart planes between common nodal end supports (7,8), the stacks being oppositely polarized to act in push-pull action with one stack expanding and the other contracting to cause the head (1) to bow. The transducer is prestressed with fibres (6) to prevent fracture.

Abstract: A flextensional electroacoustic transducer with end plates and outwardly convex shells connected to form a housing containing a transduction drive member and laterally disposed tensioning members in contact with said end plates. The tensioning members are connected by hinges allowing rotational oscillatory movement of the end plates with respect to said hinges. Another embodiment includes end plate hinges where the end plates contact the transduction drive member and hinges where the shells connect to the end plates.

Abstract: A distributed array hydrophone comprising an array of hydrophones each comprising a ceramic doublet assembly of hollow radially oppositely polarized members end held in a bobbin by decoupling means, the bobbins being linearly interconnected by semiflexible spacing members, the array being encapsulated in a vibration transmitting potting medium in a tube formed of a pressure-wave transmitting medium.

Abstract: A flextensional sonar transducer assembly includes a stack of piezoelectric elements disposed along a linear axis, a plurality of electrodes disposed between the elements, end pieces disposed at each end of the piezoelectric stack, with the end pieces having outwardly facing, generally arcuate surfaces, a band of material formed into a loop to encircle the stack and end pieces, a flexural shell disposed to circumscribe the band of material to present a generally elliptical side cross-section, with the major axis thereof being generally coincident with the linear axis of the stack, and with the shell being reactively coupled to the arcuate end portions of the band of material so that a transverse movement of the long sides of the shell causes longitudinal compression or expansion of the elongate means and vice versa, and wedge elements positioned between the shell and the arcuate end portions of the band of material for maintaining driving contact between the shell and the end pieces.

Abstract: An accelerometer for underwater acoustic sensors includes a pair of cylindrical piezoelectric crystals configured in a cantilever mode and having attached thereto an electrode segmented into four equal quadrants. In response to translational motion perpendicular to the axes of the piezoelectric crystals, orthogonal voltage signals are generated, from which the crossed dipole directivity patterns can be obtained. The symmetric use of two such piezoelectric crystals enables spurious responses, to rotational motion about an axis perpendicular to the central axis of a cylindrical container for the crystals, to be avoided.

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: The composite transducer of this invention comprises a prior art longitudinal vibrator-type transducer for transmission of energy and a piezoelectric polymer hydrophone attached to the radiating face of the transducer for the receiving function. During transmission the receiver transducer is short-circuited, and during reception the transmitter transducer is terminated in an electrical impedance that optimizes receiver response and minimizes transducer self-noise. The frequency response of the polymer hydrophone is relatively flat and extends over a much greater frequency range than the transducer.

Abstract: A flextensional sonar transducer may comprise an elliptical shell which, during manufacture of the transducer, has been distorted to permit insertion of stacks of piezo-electric ceramic plates and then released to grip the stacks and maintain them in compression, even when at design depth. The distortion requires substantial loading and may damage the shell. Herein, the undistorted shell is fitted with the ceramic plate stacks and an adjustable wedge device which is settable to provide the required pre-load. The wedge device may be coupled to an actuator, pressure sensor combination which automatically maintains a desired pre-load for different depths.

Abstract: A Tonpilz transducer having head and tail masses with an interposed active transducer section. The transducer unit is positioned within a housing which has a shoulder portion upon which rests a snubber member which extends to a position just behind the head mass. The transducer is supported from the head mass by means of a thin fiberglass tube which extends from the rear of the head mass and engages a flange portion of the snubber member in the vicinity of the housing shoulder. The housing has a waterproof covering as does the head member with the covering of the head member being secured to the covering by means of a removable strap such that the transducer assembly may be disassembled for repair.

Abstract: A transducer of acoustic energy through a water medium is fabricated in a manner which assures high reliability yet significantly reduces cost per unit by including modified conductive elements. A pair of flat conductors are interleaved sinuously through a ferroelectric stack in a mutually orthogonal relationship. The conductors are so interleaved as to electrically couple the elements of the ferroelectric stack in parallel in accordance with proven transducer design. At least one rod axially extends through the sandwiched ferroelectric elements and conductors to hold them in compression and to assure a reliable electrical connection for producing an integral hydroacoustically cooperating structure.

Abstract: A dual mode transducer has the capability of high power active transmission t two separate frequencies more than two octaves apart with broad bandwidth at both frequencies. The low frequency transducer is a standard double mass loaded longitudinal vibrator which has a head mass composed of a small array of high frequency transducers. The high frequency transducers are either half-wave resonators or tonpilz types. These high frequency transducers have a nodal plate mounting. The head mass of the low frequency transducer has a plurality of apertures which accept the high frequency transducers. The rear of each high frequency transducer is recessed into an aperture and has air as an acoustic pressure release. Both low and high frequency transducers form part of an electrically steerable array.

Abstract: An acoustic well-logging transmitting transducer employing a transmitter portion comprising stacked piezoceramic rings and a resonating metallic plate, the dimension of which determines the frequency, and a conical acoustic reflector for causing reflections to impinge omnidirectionally on the wall of the borehole at an angle to enhance shear wave component propagation. A receiving portion of similar construction can also be employed.

Abstract: A lightweight high-power transducer employs an axial array of dual-piston transducer element assemblies which are held in concentric alignment within a rigid cylindrical tube by O-rings set into grooves provided in the periphery of the pistons. The pistons have convex shaped vibratile surfaces which, in combination with the sound transmitting fluid which fills the tubular housing, causes each piston to be effectively radiating into an annular shaped tapered horn whose expanding peripheral annular area terminates into a peripheral opening placed in the circumference of the tubular housing. The combination of the inventive transducer with a tricardioid hydrophone results in a lightweight portable sonar system which achieves long-range target detection with a bearing resolution of 5.degree..

Abstract: A piezoelectric ceramic cylinder is positioned between a vibratile piston and a matched rigid mass element. To prevent corona, the electrodes on the ceramic cylinder are covered with an insulating material in the region near the edges of the electrodes where a corona might otherwise form. A low-loss rubber compound and a molded rubber support cradles the transducer assembly. A special manufacturing technique uses a standard weight supported on the cylinder to affect the resonant frequency of the cylinder and enable them to be segregated into classes according to their resonant characteristics.

Abstract: A coupling ring is bonded onto the opposite ends of a ferroelectric stack ving substantially the same thermal expansion coefficient as the stack. A thin film of silicone compound is wiped onto the axially exposed surfaces of the rings and surfaces provided in a head and a tail mass are configured to mate with them. A plurality of microspheres are mixed uniformly through a liquid adhesive and this mixture is coated onto the suitably shaped surfaces on the head and tail mass. A stress rod reaching between the head and tail mass axially compresses the ferroelectric stack and excess adhesive mixture is squeezed from between the mating surfaces. The thickness of the liquid adhesive is restricted to the diameter of the microspheres to ensure a high impedance match and upon applying the proper amount of heat, rigid joints are set up between the now hardened adhesive and the head and tail mass.

Abstract: A coupling ring is bonded onto the opposite ends of a ferroelectric stack ving substantially the same thermal expansion coefficient as the stack. A thin film of silicone compound is wiped onto the axially exposed surfaces of the rings and surfaces provided in a head and a tail mass are configured to mate with them. A plurality of microspheres are mixed uniformly through a liquid adhesive and this mixture is coated onto the suitably shaped surfaces on the head and tail mass. A stress rod reaching between the head and tail mass axially compresses the ferroelectric stack and excess adhesive mixture is squeezed from between the mating surfaces. The thickness of the liquid adhesive is restricted to the diameter of the microspheres to ensure a high impedance match and upon applying the proper amount of heat, rigid joints are set up between the now hardened adhesive and the head and tail mass.

Abstract: 1.