摘要:
An underwater acoustic transducer configured to emit a low-frequency broadband acoustic signal. The underwater acoustic transducer includes a cap in the form of a cylinder closed on one side and open on the other side. A piezoelectric plate operating in flexion is fixed on the base of the cylinder outside the cylinder. The inside cavity defined by the cylinder is open freely toward the outside medium in which the acoustic waves are to be emitted. For identical dimensions, the underwater acoustic transducer makes it possible to decrease a central frequency of emission and to increase bandwidth.
摘要:
Acoustic transmitting antennas in the form of circular rings. Several circular rings which can be dismantled of a known type are superimposed in a stack. The stack is terminated at each end by two profiled annuli. The threaded tie-rods traverse the stacks of the pre-stressing keys of the rings by the intermediary of holes drilled in these keys. The threaded tie-rods make it possible to ensure the holding of the assembly. Two jackets, inside and outside, made of rubber, cover the inside and outside faces of the stack and are anchored in grooves formed in the profiled annuli. Thereby, annular transmitting antennas can be provided which can be dismantled entirely and whose active mass to inactive mass ratio is particularly large.
摘要:
The invention relates to acoustic transducers which comprise a ceramic ring formed from a pre-stressed set of segments.It consists in using, as screws for tightening pre-stressing wedges, screws with hexagonal heads and in placing on the inner face of these wedges a plate provided with recesses in which the cants of these screw heads become anchored. This plate comprises transverse channels allowing the passage of the power supply wires for the sectors. The central screw is removed after the desired pre-stressing has been obtained.It makes it possible to improve the manufacture of these transducers.
摘要:
Embodiments of the present invention relate to a linear submersible body including a plurality of rigid segments that are articulated and can adopt relative to one another an orientation making it possible to form a rectilinear body, or a curved body of which the radius of curvature is adapted to the drum of the winch onto which it is wound. The segments are associated with couplers and configured so that a vertical rectilinear posture is naturally obtained when the device is totally submerged and towed by the ship, while the curved posture is obtained naturally by the winding of the device onto the winch. Embodiments of the invention apply to the production of linear and vertical transmitting acoustic antennas.
摘要:
The present invention relates to a device for the automatic hauling of very long elongate objects. This device in particular allows very long tubular objects of relatively flexible and delicate structure such as, in particular, underwater cables, pipes or alternatively linear sonar antennas of the “streamer” type to be handled. The device chiefly comprises traction means consisting of at least two running strips with rough surfaces which are pressed on each side of the object and drag it along in a traction movement and gripping means which constantly keep the running strips pressed against the object in order to ensure good adhesion. Another subject of the invention is means for actuating the traction means and the gripping means in a coordinated manner so that the object that is to be hauled experiences continuous traction throughout the hauling operation. The device according to the invention has the advantage of being mounted on a stationary chassis and therefore of not requiring an operating area. It is thus particularly intended for vessels where the available space is restricted, such as submarines.
摘要:
A method for controlling the navigation of a towed linear acoustic antenna. Birds equipped with variable-incidence wings are fixed onto the antenna. Through a differential action, the wings allow the birds to be turned about the longitudinal axis of the antenna so that a hydrodynamic force oriented in any given direction about the longitudinal axis of the antenna is obtained. Power and control signals are transmitted between the antenna and the bird by rotary transformers. The bird is fixed to the antenna by a bore closed by a cover. The bird can be detached automatically as the antenna is raised so that the antenna can be wound freely onto a drum. This method allows the full control of the deformation, immersion and heading of the antenna.
摘要:
Disclosed is an electrodynamic transducer designed to emit acoustic waves in a sea environment. The dome of a transducer such as this is provided with a horn sliding in the body of the transducer with an adjutage whose clearance is extremely small. This reduces the effects of a shock wave coming from a possible external explosion and prevents the tearing of the tight-sealing membrane between the horn and the body. Radial ribs increase the stiffness of this mobile structure. A toroidal, elastic air chamber provides compensation for the effects of the hydrostatic pressure and of gravity on the mobile structure. The disclosure provides transducers that are resistant to external explosions.
摘要:
Disclosed is an electrodynamic transducer designed to emit acoustic waves in a sea environment while being capable of withstanding external explosions. The lower pole piece of such a transducer is drilled with vertical holes enabling air to circulate inside the transducer in order to efficiently cool the coil that makes it work. Light metal masses that are good heat conductors, attached between the magnets which excite the pole pieces, furthermore drain the heat out of the transducer. The efficiency of such a transducer is increased by at least 4.
摘要:
An airborne buoy droppable from an aircraft into water, comprising, as a float, a balloon which inflates during its fall. Before being dropped the balloon is protected by a hood locked by a bent blade bearing on a wedge. During the fall, the scoop-shaped mechanical parts lift up, a cloth placed below an opening in the scoops inflates and frees the hood by drawing back the wedge fixed on the tongue forming an extension of the cloth.
摘要:
Method for fabricating thermally cooled electronic cards. A card of any kind is covered with a rigid heat sink shaped to fit the card and is attached thereto. The heat sink is formed in such a way that it fits as closely as possible the shape of the printed circuit. The printed circuit has components on one or both faces so that it is possible to increase the surface thermal coupling between the sink and the board. An optical sensor using a laser beam may be used.