Aquatic loudspeaker having a diaphragm

The invention relates to a submersible loudspeaker, comprised of a sound-diffusion element associated with a coil (3) consisting of an insulating support (4) and of an electrical coil (5) being connected to a peripheral magnet (6) in such a manner as to effect the transduction of an electric voltage to a musical frequency, characterized in that the sound-diffusion element is a diaphragm (2) consisting of a plastic circular planar wall of a predetermined thickness, and assigned to a bell-shaped bell (7), also made out of plastic.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of French application No. FR0500227 filed Jan. 10, 2005, which is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a loudspeaker intended to be submerged in water in such a manner that it propagates sounds.

2. Description of the Related Art

Within this field of submersible loudspeakers it was already set forth to use quartz as sound-diffusion element.

Because of the imaginable waterproofing problems, the loudspeakers with diaphragm have always been ruled out for sound-diffusion in the water even though the quartz would present the advantage that it can be encased with an insulating plastic material, most certainly providing the sought waterproofing characteristics, but offering, on the other hand, a very poor quality of sound.

In fact, submersible quartz loudspeakers do not reproduce the frequency response below 400 Hz, that is to say the bass and low registers. Insofar as listening to music in the water is extremely sensitive, of psycho-sensory nature, it results that an inexact vibro-tactile signal is rejected and the reaction of anybody is that of coming out of the water.

This type of loudspeakers has already found an application in water sports, such as synchronized swimming; thus, with the aim of relaxing, it was imagined to transfer this technique to swimming pools, Jacuzzis and bathtubs but the whole problem continued and it was considered that the spoken words and quality music could not be diffused and understood under the water.

SUMMARY OF THE INVENTION

In accordance with a first stage of the inventive process, this disadvantage was overcome by deeming that the spoken words and quality music could be perfectly diffused and understood under the water, provided that a diaphragm is used.

It is known that conventional diaphragms, made out of tropicalized cardboard, certainly withstanding hygrometry but in no case submergible, can only be envisaged.

It is by wishing to overcome this second disadvantage that the invention was realized but the solution had to consist to offer, first and foremost, a high-fidelity acoustic quality, that is to say, reproducing frequency response of the musical frequency below 400 HZ, namely, the bass and low registers, and, secondly, a perfect watertightness.

To this effect, the invention relates to a submersible loudspeaker comprising a sound-diffusion element associated with a coil consisting of an insulating support and an electrical coil which is connected to a peripheral magnet in such a manner as to effect the transduction of an electric voltage to a musical frequency, characterized in that the sound-diffusion element is a diaphragm consisting of a plastic circular planar wall of a predetermined thickness, appropriate to produce the sound in association with the coil and to orient it thanks to a bell-shaped shell, also made out of plastic, connected, on the one hand, to the diaphragm at its lower, open peripheral edge and, on the other hand, to the magnet that is at least partially housed in a corresponding opening practiced on the back of the shell; these elements constitute an assembly forming between them a sealed internal chamber inside of which is situated the electrical coil in tight connection with the diaphragm and the magnet.

The present invention relates also to the characteristics that will be shown in the ensuing description which characteristics must be considered individually or according to all their possible technical combinations.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A loudspeaker is usually constituted by a sound-diffusion element2that is connected to a coil3comprising an insulating support4and an electrical coil5, connected to a peripheral magnet6in order to achieve the transduction of an electric voltage to a musical frequency.

In accordance with the invention, the sound-diffusion element2is a diaphragm2consisting of a plastic circular planar wall of a predetermined thickness, suitable to produce the sound in conjunction with the coil3, and of a bell-shaped shell7, also made out of plastic, connected, on the one hand, to the diaphragm2on its open lower peripheral edge8and, on the other hand, to the magnet6housed, at least partially, in a corresponding opening9practiced on the back7aof the shell7; these elements constitute an assembly forming between them a watertight internal chamber10, inside of which is located the electric coil3in tight connection with the diaphragm2and the magnet6.

As clearly shown inFIG. 1or4, depending on the different embodiments, the waterproof assembly, constituted by the diaphragm2, the shell7and the magnet6, is provided on its back part7a,opposite to the diaphragm2, with a sealing body11,12, ensuring an additional watertightness and whose shape is such that it allows the obtaining of an optimal directivity of the sound.

In more details, in accordance with the example of the embodiment ofFIGS. 1 and 2, the sealing body11is obtained by a cylindrically or light bulb-shaped cast molding being provided with fastening devices13, arranged in such a manner as to allow the securing of said loudspeaker instead of an underwater light projector, replacing its bulb.

In accordance with the second example of embodiment, shown inFIGS. 4,5and6, the external sealing body12is obtained by a scallop shaped cast molding, presenting an opening plane P into which can be inserted the plane diaphragm2, which permits a cast molding of variable thickness, thin e towards the front, relatively thicker E towards the rear, in such a manner as to obtain an optimum directivity of its sound.

In accordance with another characteristic of the invention, in particular well visible fromFIG. 3, the shell7is connected to the diaphragm2near their respective peripheral borders by means of an external peripheral lip14protruding from the diaphragm2and obtained together with it from the same casting process of a plastic material; said lip14forms a catch against the internal peripheral side wall which bears by interlocking the external side wall of its lower peripheral edge8of the shell7.

Furthermore, the external fastening and the axial retaining of the diaphragm2with respect to the shell7are effectuated by means of a predetermined number of screws20, that traverse in a radial direction the peripheral lip14of the diaphragm2and then the lower peripheral edge8of the shell7.

In order to obtain the watertightness the diaphragm2presents on its plane P′, beyond its peripheral lip14, an also peripheral flange15intended to maintain the watertightness, from the moment of its application, of the lower peripheral area of the assembly, constituted by the lip14, the base8of the shell7and the screws.

In accordance with yet another characteristic of the invention, the diaphragm2is provided on its internal side with a saucer-type area16delimited by two concentric lips of which the internal one17is intended for the housing, with a preset clamping, on its outside of the insulating support4of the coil3; the other external [lip]18, constituting with the first [lip]17the adhesive container16into which will be submerged the peripheral extremity of the support4of the coil3to which, prior to its interlocking, adhesive was also applied in order to obtain an inseparable bond with the diaphragm2.

Tests have shown that excellent results were obtained with a plastic diaphragm2having a thickness of between 2 and 4 millimeters.

With respect to the utilized materials, the diaphragm2could be made out of a fiberglass reinforced polyurethane plastic while, by way of example, the shell7could be made out of filled polypropylene.

As regards the sealing body, it is made based on a silicone resin.

These different materials are not susceptible to chlorine water.

In accordance with an embodiment shown inFIG. 3a, the diaphragm2and the shell7consist of one single piece obtained from the same casting operation.