Underwater communications device

A communications device for use under water by a human speaker. A tubular base member has a mouthpiece located at one open end thereof and an inflatable air bag mounted about another open end thereof. In use, the speaker places the mouthpiece around his mouth to form an air seal therebetween and blows into the air bag to partially inflate it. When so inflated, the speaker talks into the device with voiced sounds being transmitted to the surrounding water through suitable transmitting means attached to the base member, preferably the air bag itself. During talking, the air bag receives and returns the air used by the speaker, thereby effectively preventing the escape of air bubbles from the device which otherwise interfere with communications. The air bag is preferably an elongated, flexible balloon which can be stretched into an extended position when speaking into it under water.

INTRODUCTION 
The present invention relates generally to an underwater communications 
device, and more particularly, to an inflatable and preferably stretchable 
device which allows a human speaker to talk under water and communicate 
with a human listener. 
BACKGROUND OF THE INVENTION 
Many variations of underwater communication devices are known as used from 
time to time by divers in both shallow and deep diving conditions. The 
only reliable devices previously developed have been those of 
electro-mechanical or electronic construction, especially wireless 
communication apparatus of a portable type which requires batteries, 
microphones, ear phones, transistors, and the like to be maintained in 
watertight housings and with essential watertight connections. Such 
devices are extremely expensive and the cost is doubled by the fact that 
each diver must be fully equipped to communicate with one another. 
Attempts have been made to provide non-electronic devices for talking under 
water, but no such devices are currently available in the marketplace. One 
example of a purely mechanical device is the so-called "Scuba Com" 
described in an article entitled "Mighty Mouth" by Jack McKenney, see the 
July 1969 issue of Skin Diver Magozine) as utilizing a specially 
compounded silicone-rubber diaphragm designed to provide a mechanical, air 
to water impedance matching device. However, this device just as all other 
known purely mechanical devices has the disadvantage that air bubbles are 
exhausted therefrom during its use and these air bubbles create loud 
cracking or popping sounds drowning out or severely masking vocal 
communications emitted from the acoustic diaphragm. 
In addition, such mechanical devices are limited by the need to be attached 
to a separate air supply in order to permit the speaker to fill his lungs 
after each use of one breath for speaking. When so attached to separate 
air supply, the device becomes bulky and cumbersome and must be worn at 
all times as a normal air supply. If not so attached, the speaker must 
regain a fresh supply of air from the usual air regulator after each short 
spoken message. 
An earlier underwater speaking device with an acoustic diaphragm formed by 
a thin plastic or brass disc is disclosed in U.S. Pat. No. 2,844,212 with 
the diaphragm being disposed directly in the air regulator, i.e. the air 
breathing apparatus which also includes air intake and exhaust hoses and 
an air tank. Some of the difficulties in using this earlier device are 
discussed by Laughlin et al in their subsequent U.S. Pat. No. 3,174,129, 
wherein these and other problems were again avoided by returning to an 
electromechanical combination with a microphone equipped face mask 
directly connected to the air regulator or breathing apparatus. 
BRIEF DESCRIPTION OF THE INVENTION 
The present invention eliminates the above-noted problems and disadvantages 
found to exist in conventional or previously known mechanical or 
electro-mechanical underwater communication devices by providing a simple 
and inexpensive means for preventing the escape of air bubbles while one 
is using the device to talk or communicate vocally under water. The device 
also permits the air expelled by the speaker when talking to be inhaled 
again so as to permit speech or conversations spanning several breaths 
before it is necessary for the speaker to replenish his lungs with a fresh 
supply of oxygen. 
In addition, the range of the device according to the present invention may 
be extended to 100 feet or more for the transmission of audible sounds 
under water by the simple expedient of stretching an elastic portion of 
the device during talking. These features of the invention overcome the 
need of utilizing very expensive electronic or electro-mechanical 
apparatus while still providing effective and reliable short range vocal 
communication between divers. 
Other objects and advantages of the invention will become apparent in 
considering the following detailed disclosure.

DESCRIPTION OF THE INDIVIDUAL EMBODIMENTS 
The basic design of the underwater communications device according to the 
invention is best illustrated and explained in connection with FIGS. 1-5, 
representing one preferred embodiment which is easily constructed and is 
very compact and lightweight. In FIGS. 1 and 2, the device is shown as in 
actual use as the partially inflated air bag 1 is mounted by means of its 
neck portion 2 over the outer open end of a tubular base member 3 which 
has a mouthpiece 4 formed around its inner open-end. This mouthpiece 4 can 
be an enlarged integral portion of the base member 3 as shown, or else the 
mouthpiece 4 may also be a separate resilient member fastened onto or 
fitted over the inner open end of the tubular base member 3. This 
mouthpiece in any case acts to form an air seal around the mouth of the 
human speaker while talking under water. 
The air bag 1 is preferably made as an elastic balloon which is composed of 
natural or synthetic rubber so that the neck portion 2 can be elastically 
fitted onto and securely held by the base member 3. However, for very 
inexpensive devices, it is feasible to use any thin, flexible, non-porous 
plastic film material as an air bag, e.g. a polyolefin such as 
polyethylene or polypropylene, a vinyl polymer such as polyvinyl chloride 
or even polyester or nylon films. One preferably selects those materials 
having the best sound transmitting properties such as the known silicone 
rubbers. Good results have also been achieved with natural rubber and 
neoprene. It is also possible to use rubber or plastic coated fabrics as 
still other examples of air bags. When using non-elastic materials, it is 
desirable to tightly fasten the neck portion 2 of the air bag 1 to the 
base member 3 by means of a strap or band 5 which may be an elastic band 
or other strap means to tightly hold the bag in place. When using elastic 
materials, which provide a self-fastening air bag, the band 5 may also be 
a chrome band or the like applied primarily as decoration, e.g. as 
indicated in FIG. 5. 
In place of or in addition to this band 5, the mouthpiece and the adjacent 
base member can be provided with a hand or thumb grip (not shown) in order 
to permit the speaker to easily press the mouthpiece backwardly over his 
mouth. This fitting of the mouthpiece onto the mouth and holding it in 
position while talking is readily accomplished as shown in FIGS. 1 and 2 
by gripping the base member 3 with the fingers and thumb pressing 
backwardly against the mouthpiece 4. In practice, it is generally 
sufficient to maintain a firmly pressed seal only above the upper lip of 
the speaker while permitting the bottom portion of the mouthpiece 4 to fit 
much more loosely around the speaker's lower lip. Sounds can then be 
better articulated without losing the desired air seal at the mouthpiece. 
In its preferred economical form, a mouthpiece 4a, as shown in FIGS. 3-5 
can be made of a rubber ring which can be taped or otherwise adhered to 
the inner rim of the base member 3. The size and form of the mouthpiece 
will vary, depending upon the intended use of the device. For example, for 
diving in pools and relatively shallow water depths, e.g. down to only 10 
or 20 feet, an elastomeric mouthpiece 4a may be relatively small and with 
relatively large closed air cells trapped therein. For diving at 
substantially lower depths, it is desirable to use a more flattened out 
and denser rubber or elastomeric material in the mouthpiece since the 
water pressure will begin to compress any rubber or elastomeric material 
to a smaller size as the air cells are reduced in size at higher pressure. 
The air bag 1 is shown fully inflated in the end view of FIG. 4 as well as 
the phantom line 1a in FIG. 2. During use, the air bag is only partially 
inflated and held in a slightly downwardly inclined position as it extends 
away from the mouth of the speaker, as shown in FIGS. 1 and 2, for example 
by preferably placing one hand over the top of the air bag 1 as the other 
hand presses the mouthpiece 4 over the speaker's mouth. The extended lip 6 
helps to prevent the air bag 1 from rising during use, i.e. so as to 
maintain the bag is a relatively stable inflated position at about the 
same level as the mouthpiece or slightly lower. 
As the speaker talks or voices sounds through the mouthpiece 4 into the air 
bag 1, air gradually exhaled to slowly inflate the bag 1 to its fullest 
size 1a as indicated in FIG. 2. The speaker then withdraws a small amount 
of air to partially deflate the air bag in order to again speak into the 
bag without depending upon a fresh supply of air from the usual air 
regulator or other air supply means. 
It is not necessary to completely inflate the air bag during a spoken 
phrase or to completely deflate the air bag before the next spoken phrase. 
Instead, one should ordinarily inflate the air bag to at least about 
two-thirds of its full inflation capacity and then, while maintaining a 
substantial air seal between the mouthpiece and the speaker's mouth, words 
or sounds are spoken or vocalized through the mouthpiece into the bag 
until it is more fully inflated. The speaker then sucks or withdraws air 
from the bag to partially deflate it before repeating his speaking or 
vocalizing thereinto. 
In order to enhance the length of time for speaking without removing the 
device and taking in a fresh supply of air from the regulator, it has been 
found to be especially desirable to maintain the air bag within certain 
size limits such that the air being used to speak into the bag and to 
again partially deflate the bag in one or more exchanges is approximately 
equal to or less than the so-called "respiratory dead space" of the 
speaker, i.e. the space in the mouth, throat and trachea where there is no 
exchange of carbon dioxide for oxygen. In general, it is therefore 
preferable to employ an air bag having a maximum air capacity of less than 
1.5 liters and as a safety precaution approximately one liter or less. 
Preferred air bag sizes are thus about 1/4 to 1 liter, preferably about 
1/2 to 2/3 liter. 
After repeating this speaking procedure a few times, usually not more than 
three or four times at most as an added safety precaution, the air in the 
bag can be purged with fresh air from the regulator or by the speaker 
removing the device from his mouth and breathing temporarily from the air 
regulator. The latter procedure is preferred while collapsing the air bag 
to completely deflate it and again partially inflating the bag from the 
mouth in the prescribed manner. 
The collapsed and stored position of the air bag 1 in the base member 3 is 
illustrated in FIG. 5, substantially all of the bag aside from the neck 
portion 2 being folded and inserted into the outer open end of the tubular 
base member. The bag is thereby substantially completely collapsed and 
stored within a relatively small space so that the device can be kept in a 
readily accessible pocket or otherwise attached to the diver or his other 
equipment at any convenient place. The bag, because of its shape and 
flexibility, is easily pushed into the base member and then pressed out 
again when needed for speaking or vocalizing under water. 
The primary advantage of this first air bag device as shown in FIGS. 1-5 is 
its function in maintaining a flow of air within the device when 
transmitting voiced sounds under water such that practically no air 
bubbles are expelled from the device or from the speaker to "drown out" or 
otherwise cause noise interference with the sounds being communicated. The 
solution of this particular problem offers for the first time an effective 
technique for speaking under water by mechanical means only. At the same 
time, this principle can also be adapted for use in an electro-mechanical 
device which contains an acoustical diaphragm such as a loudspeaker or 
smaller disc diaphragm as the primary means for transmitting voiced sounds 
as vibrations under water. The air bag may then act as a secondary means 
for transmitting voiced sounds or it may be limited to its main function 
of providing a flow of air entirely within the device during speaking or 
when making other voiced sounds under water. These and other variations 
based upon the separate functions of the air bag will be readily 
understood in view of the foregoing discussion, for example, so as to 
permit the air bag to be placed in gaseous communication with the 
mouthpiece by mounting it at any other open end of the tubular base 
member. Such other opening or open end may be directly adjacent to the 
mouthpiece as well as being at a maximum distance therefrom as generally 
illustrated herein. 
In using the device of the invention, it is also important for the listener 
to remain quiet and to avoid the production of air bubbles in order to 
hear the sounds being transmitted. The speaker and the listener must 
cooperate to achieve good communications under water, but the techniques 
required are easily learned even by those who are not experienced divers. 
The device of FIGS. 1-5 is best adapted for use in pools or shallow diving 
because its effective maximum range appears to be limited to about 6 to 8 
meters, i.e. approximately 20 to 25 feet, and the best results are 
obtained at an even shorter range of up to about 4.5 meters or 
approximately 15 feet. However, there are many situations where even such 
close range communication between divers is essential, for example, in 
directing underwater filming where it is necessary to communicate with 
several divers at the same time. 
An especially preferred embodiment of the invention is illustrated by FIGS. 
6-12 wherein the inflatable air bag essentially comprises an elongated, 
flexible elastic balloon or bladder capable of being longitudinally 
stretched by the speaker when transmitting voiced sounds under water, e.g. 
as indicated schematically in FIG. 8. Surprisingly, it is possible to 
increase the effective range of the device up to three or four times the 
distance achieved when using an unstretched bag or balloon. Ranges of up 
to about 23 meters or approximately 75 feet, or even more under favorable 
conditions, have been obtained with this particular embodiment of the 
invention, and such improvement in the range is attributed primarily to 
the stretched condition of the elastic air bag or balloon during its use 
both as a sound transmitting means and also as a means to retain air 
within the device to prevent the escape of air bubbles. Prior to the 
present invention, it was thought that such ranges would be impossible 
with a purely mechanical device, and the present elastically extensible or 
stretchable air bag therefore represents an unexpected advance in this 
art. 
Referring now to FIGS. 6 and 6A, the stretchable air bag device for 
underwater talking according to the invention still retains the basic 
elements consisting of the air bag itself, generally denoted by the 
reference numeral 7, the tubular base member 8, and an overall mouthpiece 
unit or housing as generally denoted by the reference numeral 9. A 
fastening strap or decorative band 10 is preferred but optional so long as 
the air bag is securely joined to the tubular base member 8 and/or the 
mouthpiece unit 9. A lanyard 11 is preferably attached to the mouthpiece 
unit 9 with a clip 12 or other fastening means for connecting with the air 
regulator, e.g. to the air regulator hose near its outlet end, so that the 
diver can use both hands while retaining the air regulator in close 
proximity to his mouth. When a fresh air supply is needed after speaking 
through the stretchable underwater talking device of the invention, this 
lanyard connection assures an immediate location and use of the air 
regulator. 
One Velcro pad 13 can be mounted on the bottom of the mouthpiece unit 9 so 
that the device can adhere to a complementary Velcro pad worn on the 
diver, e.g. on a vest, belt or the like. Such Velcro pads are well-known 
fibrous materials of hook and loop construction which adhere to each other 
when pressed together, the hooks of one pad engaging in the loops or eyes 
of the other pad. "Velcro" is a registered trademark, the product being 
readily available. Because the entire device of the invention is light in 
weight and also very compact when the bag 7 is collapsed or folded into 
the mouthpiece unit 9, i.e. within the inner tubular base member 8, as 
illustrated in FIG. 6A, it may be easily carried by the diver when not in 
use, and the lanyard attachment means 11 and 12 further ensures that the 
underwater talking device will not be lost or misplaced. 
In FIGS. 6 and 7, the elongated, flexible, elastic balloon or bladder 7 is 
shown in its relaxed, non-stretched state, the partial cross-sectional 
view of FIG. 7 disclosing in greater detail the structure and assembly of 
the various parts. It will first be noted that the balloon 7 has a partly 
frusto-conical shape in the central part thereof as provided by a number 
of pleated annular segments 14 forming a series of ridges 15 and valleys 
16 about its circumference transverse to its longitudinal axis. This 
"accordian pleating" is particularly helpful in holding the balloon or 
bladder 7 in an opened shape even when resting freely outside of the 
water. This kind of pleated structure also assists in opening out the 
balloon 7 under water as well as making it easier to fold or collapse for 
storage as in FIG. 6A. In partially inflating the air bag balloon under 
water, these pleats further offer a variation of internal volume without 
substantially changing its initial or "relaxed" elongated shape. 
The outer end portion 17 of the balloon 7 may be cylindrical in shape, 
terminating with a nipple closure 18 or any suitable tab or flap which 
facilitates the hold or grip of one hand of the diver at this end for the 
purpose of stretching the balloon as in FIG. 8. The inner end or neck 
portion 19 of the balloon or bladder 7 is tightly secured between the 
tubular base member 8 and the mouthpiece unit 9 where the latter extends 
as a closely fitting tubular housing 20 concentrically around the balloon 
neck 19 and the base member 8. Because the balloon or bladder 7 is made of 
rubber or a similar elastomeric material, it can be stretch fitted at the 
neck 19 over the tubular base member 8 and safely held in place simply by 
the normal press fit pressure of the mouthpiece tube 20 applied thereto. 
However, in order to ensure the retention of the balloon 7 on the 
mouthpiece unit 7 during stretching, it is preferable to provide a 
circumferential band member such as the elastic band 21 which resiliently 
urges and secures the neck 19 onto the base member 8. This band 21 may 
also be added as a decorative feature, either by providing a bright 
distinctive color in the band itself or by adding an additional fabric or 
chrome band thereover. The same or additional bands may also be used to 
provide fastening means similar to the lanyard 11 or the Velcro pad 13. 
Such variations are to be included within the scope of the invention. 
The mouthpiece unit 9 is made up of the contoured mouth ring 22 at its 
inner end, the tubular extended housing 20 and an enlarged bottom or 
mounting plate 23 for attachment of a Velcro pad or other fastening means 
such as a clip, snap fastener, loops for belting or the like. Such 
fastening means have been omitted from FIG. 7 since their use is optional. 
More importantly, the mouthpiece unit 9 can be effectively locked in place 
by an internal baffle member 24 in the form of a cross-bar which protrudes 
transversely into the interior of the mouthpiece unit through an arcuate 
slot 25 in the tubular base member 8. 
In the assembly of the device, reference may also be made to FIGS. 9-12 
which offer a partly schematic illustration of the mouthpiece unit alone 
(FIG. 9) and three views of the tubular base member alone (FIGS. 10, 11 
and 12). However, to achieve the interlocked assembly as shown by FIG. 7, 
the mouthpiece unit 9 can be drawn over the base member 8 from its inner 
end 26 and at least partly over the neck 19 of air bag 7 as already 
stretch fitted over the base member 8. After the baffle or cross-bar 24 
reaches the base member end 26, it must be forced the last short distance 
into the slot 25, the baffle 24 being sufficiently thin and/or resilient 
to be easily deformed as it passes from the tube end 26, and along the 
side thereof until it is released into the slot 25. Once fitted in place, 
the mouthpiece unit provides a protective locking housing as well as the 
protruding mouth ring 22. 
This mouth ring 22 is preferably flared outwardly as a tapered or gradually 
thinned out rubber flange which preferably curls backwardly and forwardly 
to form a loose-fitting mask at its outer edges 27 over a substantial 
facial area of the human speaker. In this manner, the mouth ring 22 can be 
carefully designed to conform to different facial contours while still 
forming an effective air seal. In this embodiment, it is also preferable 
to maintain a tight seal over the upper lip of the speaker while holding 
the mouth ring or mask 22 more loosely below the lower lip and around the 
lower sides of the face. For longer distance communications with this 
device, it is important to speak as loudly and distinctly as possible. 
The baffle member 24 has at least one additional function besides that of 
interlocking with the tubular base member 8 through slot 25. This baffle 
or cross-bar 24 tends to prevent water from draining into the air bag or 
balloon 7 when it is held in a slightly inclined position downwardly away 
from the mouth of the speaker. Also, because it may be not be possible to 
completely keep water out of the bag 7, the baffle 24 also helps to 
prevent water in the bag from flowing back into the mouth if the bag 
together with the mouthpiece unit 9 is inclined upwardly away from the 
mouth of the speaker. The baffle 24 thus forms a dam across the lower 
portion of the base member adjacent to the mouthpiece, i.e. adjacent the 
inner mouthpiece end of the device. It is further believed that this 
baffle member 24, if made as a thin, resilient, resonating structure, can 
act as a vibrating reed means or a "tuning bar" which may reinforce or 
enhance at least certain frequences of vibrations within the air bag as a 
resonant chamber. The stretching of the elastic air bag or balloon 7 
appears to result in changes in the natural resonance of the cavity or 
sound chamber formed by the balloon at different lengths. It is possible 
that such resonance accounts for the greater audible range achieved with 
this preferred embodiment. 
Referring again to FIG. 8, it will be noted that the air bag 7 as a 
stretched balloon or bladder offers a very different appearance from that 
shown in its rest state or relaxed position of FIGS. 6 and 7. Thus, as the 
bag 7 is stretched longitudinally, a series of grooves or folds 28 or 29 
extend over most of the length of the bag, at least in the frusto-conical 
portion thereof. These grooves or folds appear most visibly or with the 
greatest indentation and overlapping when the bag is only slightly 
inflated. Then, as the bag is held in the stretched position and slowly 
filled with more air when speaking thereinto, the bag expands slowly in a 
radially outward direction with the grooves and folds gradually filling 
out and disappearing as the bag becomes completely filled with air. It 
will be observed that the bag has the same stretched length throughout the 
speaking procedure even though it expands and contracts radially. 
The speaking procedure or method is essentially the same as that described 
with reference to the embodiment of FIGS. 1-5, except that the grooves or 
folds 28 or 29 as shown in FIG. 8 may be observed by the speaker to judge 
the point at which speaking should stop and also the point at which 
sufficient air has been withdrawn or removed in order to start speaking 
again. The size or air volume of the bag is also the same, i.e. preferably 
up to about 1 liter, and especially about 1/2 to 2/3 liter. 
Depending upon the rubber or other elastomeric material used in the 
embodiment of FIGS. 6-12, as well as its thickness and strength, the air 
bag 7 as a balloon or bladder should ordinarily be stretched at least 
about 1.2 times up to about 3 times its original non-stretched length. In 
practice, it is usually sufficient to provide a stretch of about 1.5 to 2 
times the original non-stretched length of the bag. Natural rubber and 
similar highly elastic and resilient materials are most easily stretched 
to a maximum length whereas a synthetic rubber such as neoprene is much 
more difficult to stretch, given the same size and thickness of the bag. 
Exact specifications can be readily determined for any given material, 
both natural rubber and neoprene rubber having been successfully used as 
air bags. 
Elastomeric air bags are most easily produced by dip molding from a 
suitable rubber or latex formulation. Dip molding also permits the bag to 
be formed with different thickness over its length, for example in forming 
a thicker or reinforced nose or end portion 17 to provide a firmer hand 
grip for stretching and also to avoid potential damage from finger 
pressure. Since the frusto-conical or other center portion of the bag 7 is 
used to transmit vibrations, remaining relatively loose and free to 
vibrate during the speaking cycle, the rubber or other elastomer may be 
considerably thinner in each pleat or fold 14. One can also construct this 
central portion of uniform thickness or as annular bands of different 
thickness or alternating thickness from band to band. In this respect, the 
present invention is not limited to the preferred pleated structure of the 
air bag but also contemplates equivalent vibrations which will yield 
similar results. The neck portion 19 of the air bag 7 may also have a 
greater or reinforced thickness to ensure a tight and secure fit within 
the base member 8 and the mouthpiece unit 9. Also, with a substantially 
greater thickness of material at either end of the air bag, i.e. in the 
nose 17 and the neck 19, the thinner central or intermediate portion when 
stretched forms a more natural diaphragm-like unit free to vibrate between 
the thicker and heavier nose and neck portions. In this sense, the air bag 
provides not only a resonance chamber of variable size but also a very 
large area of vibrating walls or panels formed by the central 
frusto-conical portion. 
This second especially preferred embodiment, e.g. as generally shown in 
FIGS. 6 and 6A is useful down to maximum skin diving depths, e.g. as far 
as 200 feet below the surface. Tests have shown that the range of 
audibility improves with increasing depth, and excellent results have been 
achieved at more usual depths of about 20 to 60 feet. The ability to carry 
out brief conversations at these depths is especially important to avoid 
the problems of communicating solely by hand signals or by resurfacing to 
pass along important information or instructions. Because any diver within 
range can listen to a particular speaker, groups of workers or performers 
in underwater construction work or film projects can be instructed at the 
same time in relatively complex situations. For pleasure diving, any two 
skin divers can well afford the relatively inexpensive communication 
devices of the present invention in order to spend maximum time under 
water. The method of using these improved devices is dictated to a large 
extent by the essential structure and function of the individual elements. 
However, the method has it own unique features which may be readily 
mastered by inexperienced as well as experienced skin divers.