Abstract: A transducer assembly includes a hollow support member disposed in a looped configuration and having an axial opening. A hollow transducer supported within the support member may be made from a piezoelectric material and may be provided with an axial opening corresponding to position to the axial opening in the support member. In one embodiment, the outer surface of the support member may be thinned at spaced positions as by sockets or spaced axial grooves extending partially through the support member. The support member may be thinned at strategic positions to control the vibrational frequency and the frequency bandwidth of the transducer assembly. The thinned portions of the support member may receive a compliant material such as urethane to smoothen the outer surface of the support member. In another embodiment, the hollow interior of the transducer assembly may be filled with a compliant material, such as urethane, which may be provided with air chambers.

Abstract: A compact, marine acoustical source is disclosed. More specifically, the present invention relates to a marine acoustical source capable of producing a strong primary pulse while substantially suppressing or eliminating undesired secondary pulses derivative from said primary pulse.

Abstract: In a preferred embodiment, an inter-element mounting for ceramic elements in a piezoelectric transducer stack, which mounting includes two metal plates disposed between adjacent surfaces of the ceramic elements. The metal plates are cantilevered with respect to the surfaces of the ceramic elements, such that a substantial portion of the areas of the plates between the adjacent surfaces is unsupported and, therefore, the plates have a high degree of resilience. This structure provides controlled vibrational characteristics, structural integrity for high hydrostatic pressure, versatility in design for spurious resonance suppression or elimination, dampening, and special utility for pressure gradient hydrophone stacks.

Abstract: A transducer mounting bracket for mounting a sonar transducer of a fish locator on a boat transom has an elongated base formed from a thermoplastic resilient material and including a downwardly opening channel formed at an upper end dimensioned for engagement with a boat transom. An elongated conduit extends along a front face of the base and is secured for vertical adjustment within a pair of vertically spaced aligned mounting blocks. Thumb screws extend through each of the mounting blocks for clamping engagement with the conduit. An L-shaped bracket has a vertical leg portion secured at a lower end of the conduit and a horizontal leg secured to a solenoid transducer. A signal lead connected to the transducer extends through the interior of the conduit.

Abstract: In accordance with an illustrative embodiment of the present invention, a water-proof geophone housing assembly includes a lower body member housing a seismic transducer, a cap member closing the upper end of the lower body member, an upper body member molded over the cap member and an upper portion of the lower body member, there being a molecular bond between all confronting surfaces of the members to prevent entry of moisture. The electrical lead wires extending from the transducer through the cap member and upwardly out of the upper body member are water blocked to prevent migration of water therealong.

Abstract: The present disclosure is directed to an improved telemetry system and data recovery telemetry receiver apparatus for installation with a logging cable supported sonde. In the sonde, a data stream is modulated onto a carrier after conversion by an encoder. Encoding involves conversion from a stream of binary data into four state symbols which are then encoded into seven duobinary levels. The availability of redundant levels permits correlation between encoded symbols and adjacent symbols. This is transmitted up the monocable to the surface and is recovered. The recovery involves amplification by an automatic gain control amplifier, conversion from an analog to digital form in an ADC, demodulation and reconstruction of the transmitted signal by means of a adaptive transversal filter equalizer featuring fractionally spaced sampling. Reconstructed output levels are then provided, and a slicer adjusts those values to the permitted seven levels. The data is then decoded.

Abstract: A sonic generator comprises a resonant bar, a housing and magnetic excitation units connected between the resonant bar and the housing. The magnetic excitation units are connected to the bar at highly stressed points using a mounting connection which is a sleeve having an inside diameter slightly greater than the outside diameter of the bar. A resilient elastomer such as urethane is mounted between the sleeve and the resonant member. The sonic generator may be used for grinding purposes and, in particular, may be used to grind material exceptionally fine with reduced power consumption. The bar is substantially unrestrained so as to allow substantially free vibration.

Abstract: In guidance systems such as bang-bang missiles or laser guided bombs, the cessary dynamic range is gained by switching between arrays of comparators as a function of signal strength.

Abstract: A compliant tube baffle for use in a marine environment wherein a boxlike structure (10) is surrounded by an elastomeric cover (64) and includes a pair of beam plates (12,14) separated by suitable means such as bent plate springs (18,20) which may be engageable with elastic cushioning layers (54) adhered to side shields (52). The beam plates (12,14) may be tapered with the tapered sections (34) having curved surfaces in the form of an ellipse. Damping may be provided by piezoelectric elements (58) or by constrained layers (66) of elastomeric material stressed during flexing movement of the beam plates (12,14). The beam plates (72,74) may also be separated at the edges (84) by elongated members (78,80) of solid elastomer or members (92,94) of a laminate of elastomer and rigid material.

Abstract: A single stack of double poled piezoelectric ceramic elements (202) create a monolaminar bender bar (200) which can be used in acoustic applications. The stack is lined up such that adjacent elements (202) in bender bar (200) have oppositely poled top and bottom sections. A positive voltage (230) is connected to electrical connection plates (214) which are positioned between every other piezoelectric element (202) in the stack and a negative voltage (232) is connected to electrical connection plates (214) which are between the remaining piezoelectric elements (202). Applying a voltage causes the stack to bend, wherein the piezoelectric elements (202) in the top half of the bender bar (200) all expand while the piezoelectric elements (202) in the bottom half of the bender bar (200) all contract.

Abstract: A logging tool is lowered in a borehole. The tool is positioned so that the transducer is offset from the axis of the borehole. The transducer transmits acoustic energy such that it strikes the borehole wall or casing at an incident angle that directs reflections from the borehole wall away from the transducer and at the same time allows transmission into the surrounding formations or cement in the borehole annulas between the casing and the borehole wall. Reflections of the transmitted acoustic energy from anomalies within the surrounding formations as well as cement in the annulas are received by the transducer.

Abstract: The disclosure concerns a directional hydrophonic antenna, consisting of several pairs of dipoles formed by omnidirectional hydrophones superimposed in a streamer and keeping the same reference angle for all the pairs of dipoles. The goal sought is achieved by means of a chain of superimposed, directional modules each bearing a hydrophonic sensor on each lateral face and joined by ringed tubular elements through which there goes a central rod made of fiber glass and a strand of electrical connection cables.

Abstract: A device for correcting the flight path of an air to surface missile and ding said missile to a target. A first map of a strip of ground which is transverse to the direction of flight is provided on a rotatable drum along with a second map of a strip of ground which is parallel with the direction of flight. A live image of the ground over which said missile is traveling is projected first through the first map to provide a position fix of the missile in range and azimuth relative to a target and after a correction has been made to the flight path of the missile, the live image of the ground is projected through the second map to provide guidance correction to direct the missile to the target.

Abstract: A method and apparatus for remote signal entry of control or data information from an equipment operator into an MWD system is presented. In accordance with an important feature of the present invention, the magnetometer, which is typically present in commercial MWD systems, is used as a communications channel for remote (e.g. wireless) transfer of data and/or control commands into the MWD tool. The present invention functions by replacing the direct electrical RS232 coupling with a wireless magnetic link. The invention uses the RS232 output of the operator's computer to drive its power amplifier which in turn drives the field coils in a transmitter. The axis of the field coils must be aligned with one of the sensitive axes of the magnetometer which, as mentioned, is a pre-exisitng part of the directional measurement system of the MWD apparatus. Thus, the present invention overcomes the necessity in the prior art for a direct RS232 link up between the surface computer and the computer on the MWD tool.

Abstract: The apparatus of the present invention detects the resonant frequency of a vibratory member in contact with a fluid. The detection of the resonant frequency enables the device to be used to detect the density of a fluid which it is in contact with and thereby calculate the flow rate of the fluid. The vibratory member is mounted in a housing in such a way that the chambers on either side of the vibratory member have equal volumes. The fluid enters the device through a conduit and then divides into two equal tubes on either side of an extension of a vibratory member extending down these tubes. The apparatus for measuring the resonant frequency of the vibratory member is mounted on the vibratory member and is comprised of a piezoelectric element coupled to a driver circuit in a feedback loop.

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: A sonde for aquiring seismic signals in a borehole, the sonde comprising: a detector module (30) enclosing at least one seismic sensor (G); an elongate body (21) having a lateral cavity (22) suitable for receiving the detector module (30); a resilient suspension (40, 50) connecting said module to said body; and an anchor member (12, 13) disposed on the opposite side of said body to the side in which said cavity is disposed. The sonde is characterized by the fact that the resilient suspension exerts a force on said module suitable for displacing it out from the cavity and for pressing it against the wall of the borehole so as to couple it to said wall, together with means (41, 43, 51, 53, 60) which are provided to retract the module into said cavity against the force exerted by the resilient suspension.

Abstract: A diaphragm tensioning arrangement for a Sell-type ultrasonic transducer assembly is disclosed. The transducer includes a fixed backplate having a substantially planar electrically conductive front surface and a diaphragm having a front surface and back surface, the back surface of the diaphragm overlying the substantially planar surface of the backplate. The diaphragm includes an insulating layer adapted to contact the backplate and a conducting layer electrically isolated therefrom. The diaphragm tensioning arrangement includes means for applying a load to the front surface of the diaphragm in order to maintain diaphragm tension. A groove disposed in the backplate extension or base has at least one groove opening into its front surface. A tension element engages the front surface of the diaphragm pressing a portion thereof into the groove in order to maintain diaphragm tension.

Abstract: A hydrophone device is provided with a piezoelectric ceramic-polymer composite of 0-3 connectivity in which the piezoelectric filler comprises a solid solution of PBTiO.sub.3 -BiFeO.sub.3 wherein the solid solution contains 50-80 wt. % of the BiFeO.sub.3. The piezoelectric ceramic-polymer composite has large hydrostatic piezoelectric charge and voltage coefficients which are desirable in hydrophone devices.

Abstract: A protective mask is provided, which contains the eyes, nose and mouth, crising a protruding lens so as to provide increased peripheral vision and preferably a nose cup which is shaped to provide a channel for passing defogging air to the lens, and peripheral areas of the mask which fold inward to form the seal.