Abstract: A lithotripter for the contactless comminution of concrements in living beings includes a flat coil cooperating with a juxtaposed membrane which upon energization of the coil produces shockwaves in an adjacent liquid, the liquid being in contact with the body of the living being, there being an insulation between the coil and the membrane, the coil having two or three parallely positioned wires for multiple windings with each winding having the same number of wires, and being electrically connected in parallel.

Abstract: An underwater acoustic projector including a Class IV flextension shell, preferably in the form of an ellipsoid, is connected to and driven by two substantially identical electromagnets having mutually opposing pole faces and having a common spatially uniform air gap which is centered between the pole faces. The coils of the two electromagnets are connected in series and when excited by a controlled current, generate a mutually attractive variable reluctance force which causes the pole faces to be attracted toward one another. The shell secured to the electromagnets elastically flexes along one of two mutually perpendicular axes resulting in a volumetric displacement of the outer surface of the shell.

Abstract: A noise cancelling watertight transducer that converts sound wave to electromagnetic waves or conversely electromagnetic waves to sound waves comprises a hollow shell having curved walls mounted for movement in a resilient container. A freely movable inertial mass is located inside said shell. The inertial mass resists movement when a force is applied thereto. Signal translating means are incorporated therein consisting of either an electromagnetic device, a piezoelectric element or voltage potential senative element that is mounted in and connected with said shell and interacts with said inertial element. In response to appropriate signal some embodiments of the instant invention acts as a bidirectional device converting electrical signal to acoustical signal or conversely acoustical signal to electrical signal.

Abstract: An underwater transducer system reproduces high-fidelity audio signals underwater, and detects and monitors low levels of sound activity, both adjacent to a body of water such as a swimming pool, and in the water. The system includes an underwater housing for a diaphragm that directly contacts the water, a coil assembly movable within the housing and rigidly connected to the center of the diaphragm by a tubular member of the coil assembly engaging a cylindrical boss portion of the diaphragm. The housing can be suspended by an elongated cord member from a wall coping, or mounted within a wall fixture structure. The system can have a source of illumination, a conduit from the source terminating in the housing on the coil axis proximate the diaphragm, and an optical element sealingly protrudes the diaphragm for transmitting light-amplified illumination into the water.

Abstract: A transducer to be used in a shock wave generator including a support, at least one energizing coil mounted on the support; at least one, preferably two copper or silver membranes are placed on the coil and insulated from each other; an outer, stainless steel membrane is grounded and an electrical insulation is interposed between the first and the second membranes.

Abstract: A shock wave source of the type suitable for disintegrating calculi in the body of a patient has a shock wave tube which is filled with a shock wave conducting medium, such as a liquid, which is closed at one end by a flexible cover which can be pressed against the patient by the pressure of the medium, and closed at the other end by a membrane of electrically conducting material. A flat coil is provided which is connected to a high voltage pulse generator. An insulting layer is disposed between the membrane and the coil such that the membrane is insulated from the coil at both ends of the coil.

Abstract: A shock wave source for use in a shock wave generator in an apparatus for extracorporeal lithotripsy treatment of a patient has a shock wave tube filled with a shock wave propagating medium with one end closed by a flexible sack for coupling to the patient, and an opposite end closed by a membrane having at least a portion thereof which is electrically conductive, and a coil disposed adjacent the membrane and connected to a high voltage pulse source. When high voltage pulses are applied to the coil, an electromagnetic field is generated which rapidly repells the membrane, thereby generating a shock wave. The membrane has a flexible base covered by a number of discrete laminae of conductive material. At least some of the laminae may have respectively different mass moments of inertia and/or electrical conductivity. The shock wave source is suitable for treating calculi such as kidney stones.

Abstract: This invention relates to an underwater transient sound generator capable of operating at substantial depths. The pulse produced by the generator is used to determine subbottom terrain in underwater surveying. Essentially, the invention consists of an electromagnetic coil, which is embedded in an annular support body with a central hole. A piston is located next to the coil, but is separated therefrom by a dielectric sheet. A rubber seal and spring are used to locate the piston in position. A body portion extends back from the support body with two open ends. The rear end is covered with a water tight flexible diaphragm and the front end connects with the central hole of the support body, defining a watertight pressure transfer space, containing a pressure transfer medium. The coil is capable of being energized to rapidly displace the piston to a forward position. Two embodiments are shown in which the pressure transfer medium is either a gas or a fluid.

Abstract: A deep-water low-frequency transducer employs a collapsible air chamber to equalize the internal transducer air pressure with the external hydrostatic pressure at the submerged operating depth. A capsule containing a highly pressurized gas is mounted inside the collapsible air chamber and an automatic valve mechanism releases the gas to inflate the collapsed air chamber at a predetermined depth, beyond which any further reduction in the air volume would impair the operation of the transducer. With the collapsed air chamber restored to its original full volume, the transducer will operate satisfactorily at increased water depths.

Abstract: An electromagnetic transducer for use in generating transient acoustic pulses in particular for medical purposes such as the destruction of kidney stones. The transducer comprises at least one pair of conductors, of which one is held against movement by a carrier having a high sonic impedance, whereas the other is displaceable with respect to the first to actuate an emitter for generating a pressure pulse as soon as both conductors are traversed by contradirectionally oriented currents so as to repel one another. The conductors of each pair are laid parallel to each other and so connected electrically that the portions adjacent to each other in each case of the cooperating first and second conductors can be traversed by the currents fed into the conductors contradirectionally to generate repulsive forces and equidirectionally to generate attractive forces.

Abstract: A system for producing pressure or shear-waves in a solid medium uses a wave generator with at least one primary induction coil and at least one short-circuited secondary coil. The short-circuited secondary coil is rigidly connected to the solid medium for directly transmitting to the solid medium the repulsion force generated between the primary and secondary coils by a short-circuit current caused to flow in the secondary coil when electrical power is applied to the primary coil. Thus, the system is a transformer in which the short-circuited secondary coil is directly used as the tool for the wave application.

Abstract: The invention is directed to a shock wave generator for an apparatus for non-contacting disintegration of calculi in the body of a life form which includes a housing filled with a liquid, a membrane closing the housing and connected thereto along the edge thereof, and a device for pulse-like driving of the membrane. In order to suppress overstressing of the membrane and deformations of the membrane which are diletorious in view of the focussability of the shock waves, a tubular spring resilient in the moving direction of said membrane are provided between said housing and said membrane, said membrane being connected to said housing with said resilient spring in a fashion essentially free of bending moment.

Abstract: A shock wave source of the type suitable for treating calculi in the body of a patient has a shock wave tube filled with a shock wave-conducting medium which is closed at one end by a flexible cover adapted to be pressed against the patient, and closed at an opposite end by a membrane. A flat coil is disposed parallel to and spaced from the membrane, with an insulation layer therebetween. The coil is connected to a high voltage pulse generator. The membrane consists of an insulator disc having electrically conductive tracks thereon, preferably concentrically disposed. The conductive tracks constitute a significantly lengthened path which must be overcome in order to generate an arc between the membrane and the coil, so that unwanted arcing is substantially eliminated.

Abstract: A shock wave generator for an installation for non-contacting disintegration of calculi in the body of a life form has a coil with spirally arranged turns and a membrane formed of an electrically conductive material lying opposite said coil and terminating a space filled with a fluid, the coil being connectable to a high-voltage supply. To assure a high useful life of the membrane without a significant reduction in the efficiency of conversion of electrical energy into shock energy, a distance increased in comparison to regions of low voltage difference is present between the coil and the membrane in regions of high voltage difference between windings of the coil and the membrane.

Abstract: A shock wave generator for an apparatus for non-contacting disintegration of calculi in the body of a life form has a membrane of electrically conductive material which terminates a volume filled with a shock wave conducting medium, and a coil having windings disposed adjacent the membrane. The coil is connectable to a high voltage source with two terminals. For maintaining a long useful life of the membrane without significantly reducing the efficiency of converting electrical energy into shock wave energy, the membrane is provided with a potential such that a positive difference in potential is present between one terminal of the coil and the membrane, and a negative difference in potential is present between the other terminal of the coil and the membrane.

Abstract: A wide-range audio frequency underwater transducer is designed to make use of a massive small diameter vibratile piston driven by electromagnetic oscillatory forces to transmit omnidirectional uniform sound pressure level over the frequency range 100 Hz to 5 kHz. The rugged transducer design is adapted for low-cost mass production and can be used as a highly reliable expendable reference standard of source level for the calibration of in-situ stationary or moving sonar receiving systems. The magnitude of the source level can be accurately controlled by the magnitude of the electrical current supplied to the electrical winding over the entire frequency range of operation. A pressure equalization system is included in the design that permits use of the transducer at any depth down to 500 feet.

Abstract: A speaker system having a magnet and voice coil are mounted within a dome-shaped enclosure in such a way as to be capable of transmitting sonic vibrations and audio waves through a liquid medium or solid structure, the dome-shaped enclosure cooperating with the magnet and voice coil in such a way as to greatly enhance the waves and sonic vibrations generated to the other medium or structure.

Abstract: An electromagnetically driven vibratile piston underwater transducer element generates acoustic intensity levels in excess of 25 peak Watts per square inch of radiating surface in the low audible frequency region within the approximate range 500 to 2500 Hz. The design achieves an efficiency greater than 50% and a very low Q of less than 2. The electromagnetic design employs two separate independent air gaps and a unique mechanical coupling system that combines the electromechanical forces generated in each gap in the proper phase and transmits the combined oscillatory force to drive the vibratile piston.

Abstract: The power handling capacity of a high-power low-frequency underwater transducer including an inertial mass-loaded vibratile piston assembly is greatly increased by increasing the heat conduction from the inertial mass member by designing the vibrating structure to place a surface area portion of the inertial mass member in direct thermal contact with the water environment in which the transducer is submerged. In order to reduce the sound radiation from the exposed surface of the submerged inertial mass member and to obtain a broadband response with a Q equal to 1 or less, a novel rigid hollowed piston construction is described which greatly reduces the weight-to-stiffness ratio of the vibratile plate and achieves the desired low Q as well as a reduction of sound radiation from the exposed inertial mass surface by at least 20 dB below the radiation from the surface of the vibratile plate member.

Abstract: An electromagnetically driven vibratile piston underwater transducer element generates acoustic intensity levels in the order of 50 peak Watts per square inch of radiating surface in the low audible frequency region in the vicinity of 1 kHz. The design achieves an efficiency greater than 50% and a very low Q of less than 2. The air gap is designed to seat mechanically if the unit is operated accidentally at high-power levels while acoustically unloaded thereby protecting the spring assembly from unsafe amplitudes of vibration. The mechanical protective design also serves to protect the transducer vibrating structure from failure if the transducer is exposed to the proximity of an underwater explosive shock wave. The transducer construction results in a minimum overall length so that when the transducer element is mounted in a planar array attached to the hull of a vessel the projection of the radiating surface of the array from the surface of the hull is minimized.

Abstract: An electrodynamic transducer has broadband operation and is suitable for erwater use. The transducer has a flexible rubber seal to assist in keeping the unit watertight. New features include a large flared air passage, a coil of wire that is rectangular in cross section and is routed through the center of a hollow centering shaft. In addition, a piston is machined out of beryllium copper with the piston attached to the shaft at the dome center and the skirt spider center. The transducer is designed to operate with the magnet having its outer pole piece in contact with the seawater.

Abstract: A magnetic drive is provided for a flextensional transducer in order to adapt the flextensional transducer for operation at increased ocean depths without the necessity of liquid filling and complex decoupling devices. In one embodiment an electro-magnetic actuator is positioned between the walls of the flextensional shell and is driven electrically so as to deflect the shell walls outwardly. The magnetic actuator in one embodiment includes a permanent magnet and pole pieces supported on one of the interior walls of the shell, with a moving coil positioned between the pole pieces and supported on a diametrically opposite wall of the shell. In an alternative embodiment, the magnetic actuation may be in the form of a rod of magnetostrictive material between opposing interior walls of the shell, which is actuated by an overwound electrical coil, with the shell being of magnetic material such as magnetic iron.

Abstract: A directional hydrophone comprises a plurality of coil elements each disposed in an air gap in a common magnetic circuit. In a first embodiment of the invention two coil elements each have a single degree of freedom of motion which is orthogonal to the other. The force due to an acoustic wave impingent upon the hydrophone is resolved into two orthogonal components by the two coils which give rise to two distinct electrical output signals proportional to the sine and cosine respectively of the angle at which the acoustic wave arrives. In another embodiment of the invention each coil element has two degrees of freedom of motion and the movement of each of the coil elements is resolved into two orthogonal components by the effective length of the coil which varies in a known manner with the angle of coil motion with respect to the polarity of the magnetic circuit.