Underwater Voice Communicator

This invention pertains to underwater communicators for use with self contained underwater breathing apparatus (scuba) and the like for permitting divers to readily communicate while underwater.

It is a well-known principle of wave propagation that when sound waves strike a surface separating mediums having significant differing impedances, a portion of the wave is reflected and hence not transmitted through the second medium. This principle of wave propagation has created significant barriers to divers attempting to communicate underwater. This is due to the fact that the sound waves emitted by the diver must pass from air to water. Of course, an air chamber is formed about a diver's mouth to enable a diver to breathe while underwater. Thus, at the surface defining the boundary between the air chamber and the surrounding water a significant portion of the sound wave is reflected. This phenomenon prevents a diver from projecting his voice to the surrounding water where it can readily be heard by other divers.

Several voice communicators have been developed in an effort to enable divers to communicate while underwater. The following U.S. Pat. Nos. are indicative of the previously known underwater communicators: 3,348,537 Miller; 3,348,539 McDonald; 4,527,657 Payne; and 4,527,658 Payne. The afore-mentioned arrangements for underwater voice communicators have been unable to effectively minimize the reflection of sound waves at the layer separating differing mediums.

It is, therefore, a primary object of the present invention to provide an improved underwater voice communicator.

Another object of the present invention is to provide an underwater voice communicator with an acoustical lens for focusinq acoustical energy at a predetermined area.

Yet another object of the present invention is to provide an acoustical lens which can readily regulate the speed of acoustical energy impacting the lens for maximizing the concentration of acoustical energy impacting a predetermined area at a specific time.

A further object of the present invention is to provide a transmitter for transmitting acoustical energy from a first medium to a second medium wherein the transmitter has an impedance substantially equal to the second medium.

Still a further object of the present invention is to provide a protective housing for the transmitter of the present underwater voice communicator for preventing damage thereto.

Yet another object of the present invention is to provide an underwater voice communicator that can be formed integral with a standard diving regulator.

Yet another object of the present invention is to provide an underwater voice communicator than can be formed from one piece with a mouth piece forming an air chamber about the diver's mouth.

A further object of the present invention is to provide an acoustical lens having a plurality of inclined passageways extending therethrough for regulating the speed of acoustical energy through the lens.

FIG. 1 is a fragmentary side elevation view of a mask assembly employing the underwater voice communicator formed in accordance with the present invention.

FIG. 2 is a perspective view of the preferred embodiment of an underwater voice communicator formed in accordance with the present invention.

FIG. 3 is a cross-sectional view of the preferred embodiment of the underwater voice communicator of the present invention.

FIG. 4 is a fragmentary exploded view of the preferred embodiment of the underwater voice communicator of the present invention.

FIG. 5 is a front elevation view of the acoustical lens formed in accordance with the present invention.

FIG. 6 is a cross-sectional view of the acoustical lens depicted in FIG. 5 taken along lines 6--6.

Referring to FIG. 1, an underwater mask assembly A includes a mouth piece B defining an air chamber about the diver's mouth, an underwater voice communicator C, and a regulator D.

The underwater communicator C, as best seen in FIG. 3, includes a housing 2, an acoustical lens 4, a transmitter 6, a seal 8, and a sub-housing 10. The housing 2 includes an air passageway 12 and a cylindrical sleeve 14. Housing 2 further includes a cylindrical section 16 and an annular substantially conical shaped section 18. Section 16 has a recess 20, best seen in FIG. 2, formed along its outer periphery for recharging an annular projection 22 extending from mouth piece B. Annular projection 22 forms a substantially watertight seal about the outer periphery of underwater communicator C. Section 18 includes first and second ends 24 and 26 and acoustical lens 4 is positioned in passageway 12 of housing 1 and 2 adjacent end 24 of section 18. Section 18 is tapered in the direction of end 26 to facilitate the channeling acoustical energy emitted by the diver through air passageway 12 to transmitter 6. The cylindrical sleeve 14 is externally threaded for threaded engagement with sub-housing 10.

Although mouth piece B and communicator C are formed, as shown in FIG. 1, from separate pieces, it is within the purview of the present invention to form them from a single piece. Further, the mouth piece B can be eliminated altogether by positioning the communicator C in the regulator D.

Referring to FIGS. 5 and 6, acoustical lens 4 includes front face 28, rear face 30, vertically extending plates 32 and angularly extending plates 34. The front face 28 is substantially planar while the rear face 30 is substantially concave in shape. This type of lens is commonly referred to as a converging lens. It will be readily appreciated that the specific configuration of acoustical lens 4 can be varied in order to adjust the focal point of the lens as may be needed. Vertically extending plates 32 are spaced and extend parallel to each other. Similarly, plates 34 are spaced and extend parallel to each other. Plates 34 form an acute angle with the front face 28 of acoustical lens 4. Plates 34 are positioned relative to plates 32 to form a plurality of passageways 36, extending through acoustical lens 4, best seen in FIG. 3. As can be readily seen from FIG. 5, the acoustical lens 4 in the preferred embodiment has a substantially circular cross-section. However, the cross-section of the acoustical lens may be varied to meet the specific conditions of a particular application of the present invention.

The transmitter 6 is positioned within seal 8 located in cylindrical sleeve 14 of housing 2, as best seen in FIG. 3. The transmitter 6 is formed from lead or similar materials having an impedance substantially identical to that of water. The transmitter 6 includes first and second ends 38 and 40. The first end 38 is exposed to air while the second end 40 is exposed to water. The transmitter is tapered from end 38 to end 40 in order to facilitate the propogation of acoustical energy in a forward direction. First end 38 of transmitter 6 is positioned at the focal point of acoustical lens 4.

Referring to FIGS. 3 and 4, the sub-housing 10 includes a plurality of radially extending holes 42 and an axially extending hole 44. The holes 42 and 44 extend through the sub-housing 10 and communicate with chamber 46. Thus, when the voice communicate C is submersed, the chamber 46 readily fills with water. The sub-housing 10 prevents foreign objects from impacting transmitter 6 and thus avoids deformation of the same.

As previously mentioned, when acoustical energy passes between mediums having differing impedances, a significant portion of the acoustical energy will reflect from the surface separating the two mediums. In order to overcome the effects of reflection upon the transmission of sound between differing mediums, the present invention has designed an underwater voice communicator having an acoustical lens that will maximize the concentration of the acoustical energy at the first end 38 of transmitter 6. The acoustical lens 4 achieves this by focusing and regulating the speed of acoustical waves impacting it.

Focusing of the acoustical energy emitted by the diver is achieved by positioning end 38 of transmitter 6 at the focal point of lens 4. By focal point, it is meant that point at which a significant portion of the acoustical energy is directed by lens 4. Before proceeding to discuss the speed regulating feature of acoustical lens 4, one must understand some general principles of the travel of sound waves through acoustical lenses. As can be readily seen from FIG. 3, acoustical waves E impacting the outer portions of the lens 4 have a greater distance to travel than acoustical waves F impacting the lens 4 at its center (the unregulated travel of waves E and F is shown in dotted lines). Thus, without proper regulation, the acoustical wave F will strike first end 38 of transmitter 6 prior to acoustical wave E. Therefore, the concentration of acoustical energy at first end 38 of transmitter 6 will be minimal. As a result, the phenomenon of reflection will be accentuated. The present invention has overcome this disadvantage by providing a plurality of inclined plates 34. As can be readily seen from FIG. 3, the inclined plates 34 will direct the acoustical wave E toward first end 38 of transmitter 6. Further, the plates 34 will initially reflect the acoustical waves F away from the first end 38 of transmitter 6 and subsequently an adjacent plate 34 will reflect wave F toward end 38, thereby increasing the distance that acoustical wave F must travel. As a result, acoustical waves E and F will impact first end 38 at substantially the same time. Therefore, the acoustical energy impacting the transmitter 6 will be maximized thus reducing the effects of reflection.

It should be noted that the plates 34 formed in the lower end of acoustical lens 4 will direct acoustical waves E away from transmitter 6. In order to further maximize the concentration at transmitter 6 the plates 34 formed in the lower portion may be positioned such that they extend upwardly towards the transmitter 6. However, the acoustical lens 4 is effective for permitting underwater communication between divers in the same area while minimizing the costs of manufacture.

The transmitter 6 is formed from lead or other suitable material which has substantially the same impedance as water. Therefore, the acoustical energy transmitted by the transmitter 6 to the surrounding water in chamber 46 will experience little, if any, reflection or refraction.

In an alternative embodiment, the acoustical lens 4 can be formed from a solid having a density which varies along the cross-section of the lens. The density along the cross-section of the acoustical lens should vary proportional to the distance that any acoustical wave impacting the lens at a specified point must travel to the transmitter. By varying the density of the material, one can regulate the speed of the sound waves impacting the transmitter 6 in a similar manner to acoustical lens 4.

While this invention has been described as having a preferred design, it is understood that it is capable of further modification, uses and/or adaptions of the invention following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, such as may be applied to the essential features set forth, and fall within the scope of the invention and of the limits of the appended claims.