US1414295A - Submarine sound receiver - Google Patents

Description

IVI. IVIASON.

SUBIVIARINE SOUND RECEIVER.

APPLICATloN FILED1uNE25,1919.

Patented Apr. 25

lulu /uMm INVENTOR.

PATENT OFFICE.

MAX MASON, F NEW LONDON, CONNECTICUT.

SUBMARINE SOUND RECEIVER.

Specification of Letters Patent.

Patented Apr. 25, 1922.

Application led June 25, 1919.. Serial No. 306,6844.

To all'wkom t may concern Be it known that I, MAX- MAsoN, a citizen of the "United States, residing at New London,in the county of New London and State `of Connecticut, have invented new and useful Improvements in Submarine Sound Re` c ei'vers, of which the following is a' specication.

The present invention relates to sound receivers and mo're particularly `toso-called acoustiealsound receivers of the diaphragm type. The object of the invention is to provide' asensitive substantially non resonant sound receiving diaphragm. To accomplish this result I employ a substantially nonresonant, preferably thin diaphragm, which is supported at a plurality of points distributed over-.its area in such a manner as to render it substantially non-resonant and substantially equally responsive overA a wide range of sound frequency.

' While the diaphragm sound receiver may be used for many purposes, such for eX- ample as a diaphragm for. a telephone microphone, it is particularly applicable for submarine sound reception and I have illustrated the invention as` embodied in areceiver for submarine work. For submarine sound detection and particularly for a multiunit submarine sound receiving device, it is essential thatthe in ividual sound `receiv- 'ers be substantially non-resonant, otherwise they will individually vibrate at their own frequencies and out of phase, so that exact superposition `in regard to phase of the sounds received from the 'separate diaphragms will not occur at the collecting point and accurate focusing will be impossible.

In the drawings which illustrate the preferred embodiment of my invention Fig. 1 is an elevation of the receiver, Fig. 2 is an elevation of the backing plate, Fig. 3 is an elevation of one of the larger of the two wire guaze sheets, Fig. 4 is an elevation of one of the smaller of the gauze sheets, Fig. 5 is a section through the receiver along the line V-V of Fig. 1, Fig. 6 is a` section through the receiver along the line VIVI of Fig. 1, and Fig. 7 is a section through a receiver illustrating a modification.

Referring to the illustrated embodiment of the invention, the receiver comprises a comparatively heavy metal backing late 1 through which passes a pipe 2 which3 an f path or column from the receiver to der the sound waves.

forms the sound detecting instrument. A thin da phragm 3 is placedV in fron-t of the backing plate l leaving an air chamber between it and the backing plate. The function of the thin diaphragm 3 is to form a yielding wall orseparation-between the water in which the receiver is immersed and the air in the chamber 4. A thin sheet of practically any ,waterproof material may be used for this diaphragm. 'The diaphragm may be made of thin sheet metal such .as aluminum, copper, brass, or the like, or may be made of bakelite, rubber, etc. When the diaphragm 3 ismade of metal it may be conveniently secured to the backing plate D by being spun over the edge and soldered, as shown in the drawings. In the air chamber 4 is placed a backing for the diaphragmwhich will support the diaphragm at a plurality of points against the hydrostatic pressure of Water in which it is submerged.

I have found that ordinary copper wire gauze is a suitable backing material .for the diaphragm. It furnishesa large number of irregularly distributed supporting points for the diaphragm. The supporting points thus furnished are not rigid but are yielding in various degrees and provide a plurality of restoring forces of different intensities for the diaphragm as it vibrates un- This fact combined with the viscosity and radiation damping which is effective `on the diaphragm, produces an instrumentl which is sensitive over a Wide range of frequencies and sufficiently non-resonant for use in multiple units. The viscosity damping is due to the. viscous re action of the air in the thin cavity 4, the effect being a frictional resistance to the motion of the diaphragm. The radiation damping is due to the energy sent up the acoustical tube 2 as well as the energy sent lback into the water by the motion of the diaphragm 3.

The wire gauze backing is preferablyI made in two pieces as illustrated in the drawing, a large piece 6, which extends over 'the entire inner face of the'diaphragm, and

a smaller. piece 7 which is placed under the middle of the diaphragm over the mouth ofl the air tube 2.

While I prefer to use wire gauze Vor similar material which furnishes a large number of irregularly distributed and irregularly yielding supporting Apoints for the diaphragm, a plurality of point supports may be otherwise provided. For example, a plurality of diaphragm supporting points may be `formed integral with the backing plate l as shown in themodiication illustrated in Fig. 7. f

In order to break up any resonant effect of the diaphragm 3 vibrating as a Whole, I prefer to cut the diaphragm in from its edges at a plurality of places as indicated by vreference numerals 8 in Fig. 1. The sheet of wire gauze G is similarly cut away as indicated at reference numerals 9 on Fig. 3, and the edges of the piece of wire gauze 7 are notched as indicated by reference numerals l0 on Fig. 4, to register with the cut away portions 8 of the diaphragm.

In assembling the receiver the piece of wire gauze 6 is placed on the backing plate l, then the sheet of wire gauze 7 placed over it, and over this is placed the diaphragm 3 and the edges of the diaphragm are turned over the metal plate l. The pieces of wire gauze 6 and 7 are located so that their cut away portions 9 and l0 register with the cut away portions 8 on diaphragm 3. After the parts are assembled as above described, the edges of the cut away portions 8 of the diaphragm arev soldered or otherwise fastened in a water tight manner through the slots in the wire gauze to the face of the backing plate 1. This mode of attaching the diaphragm 3 breaks up the diaphragm into a comparatively large number 'of smaller diaphragm areas, preventing the diaphragm vibrating as a whole. Vhile this breaking up of the diaphragm area is not essential it has proved of advantage. The diaphragm being of a thin iexible material assumes the shape of the backing against which it is pressed under hydrostatic pressure, taking the form shown in Fig. 5, the middle of the diaphragm being bulged outwardly over the double thickness of wire gauze. This double thickness of Wire gauze is applied at the center to give a greater cross-sectional area to the air passage connecting the tube 2 with the receiving cavity 4.

While I have specifically illustrated and described the preferred embodiment of my invention, it is to be understood that the invention is not limited to its illust-rated embodiment but may be otherwise embodied within the scope of the 4following claims:

I claim:

l. A sound receiver comprising a substantially nonresonant diaphragm divided into a plurality of sectors and adapted to cooperate with a similarly divided wire gauze backing, said wire gauze giving a plurality of non-rigid supporting points adapted to withstand hydrostatic pressure, substann tially as described.

2. A sound receiver comprising a substantially non-resonant diaphragm and a backing comprising a plurality of non-rigid supporting points therefor exerting unequal restoring forces on the diaphragm, substantially as described.

A sound receiver comprising a diaphragm arranged to be subjected to hydrostatic pressure and a backing for the dia phragm comprising a sheet of wire gauze contacting with it at a plurality of points distributed over its area, substantially as described.

4. Ahsound receiver comprising a backing plate, a non-resonant diaphragm over the platdivided into a plurality of sectors, and a plurality of supporting points separating and holding the diaphragm away from the backing plate, substantially as described.

MAX MASON.

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