US1419596A - Microphone mounting - Google Patents

Description

E. C. WOOD.

MICROPHONE MOUNTING.

APPLICATLON FILED APH,25,19'18.

Patented June i3, i922.

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UNTTED STATES PATENT DFFTQL@ EDWARD C. WOOD, OF SOMERVLLE, MASSACHUSETTS, ASSIGNOR TO SUBMASRINE SIGNAL COMPANY, 0F BOSTON, MIASSACHUSETTS, A CORPORATION OF MAINE.

MICROPHONE MOUNTING.

Application lcd April 25, 191e.

T o fr?? :clio/n if 'may concern:

Be it known that I, EDWARD C. lvooo, of Somerville. in the county of Middlesex and State ot Massachusetts, a citizen of the Vnited States. have invented a new and uset'ul Improvement in Microphone Mountings, ot' which the t'ollowing is a specification.

My invention relates especially to the mounting ot' a microphone upon a tuned diaphragm such that external pressure will not change the pitch of the diaphragm. My invention is more particularly adapted for cases in which it is necessary or desirable to hang the microphone overboard from a vessel or pier.

A microphone when used as a submarine receiver is usually mounted on a metallic diaphragm which preferably is tuned to receive vibrations ot a given pitch, more or less to the exclusion of other sounds. When mounted in a casing of such a character as not to interfere with its reception of sound waves t'rom the surrounding water, upon submerging this diaphragm it is submitted to a pressure due to its depth of submersion, which interferes more or less with the pitch to which it is tuned. The purpose ot my invention is to provide means such thatthe diaphragm will maintain tits normal pitch however deep it may be submerged, the pressure on both sides ot' the diaphragm being automatically equalized, so that the device asy a whole may bc self-equalizing.

My invention will be understood by reference to the drawings in which it is shown in its preferred form.

Figure 1 is a front elevation,

Fig. 2 is a vertical section, and

Fig. 3 is a side elevation of a device in which my invention is embodied.

A is a circular casing having a chamber a at its centre and an opening L1 opposite said chamber closed by a screw plug a2. Opposite the"opening (1,1 is a second opening a3. The front tace of the casing has two circular projections thereon, one forming a rim B to which is attached by screws a diaphragmholding ring C, the other B1 being a bridge Y over which the diaphragm D is stretched. The diaphragm D is provided with openings near its edge tor the screws 7) and its outer edge is preferably turned outwardly and is clamped against the eriphery of the ring C Iby a hoop c which. may be soldered or driven into place to prevent the diaphragm Specification of Letters Patent. Patent-@d Jun@ 113, 1922,

Serial No. 230,799.

t'rom yielding under the strain set up by the ring E.

The diaphragm D is timed by means of the ring E which screws into the ring C.

The ring E is provided with Spanner holes e to screw it into place.

It will be noted that the tuning ring E is larger in diameter than the bridge B1 and smaller in diameter than the holding ring C so that by screwing it against the diaphragm it will strain the diaphragm over the bridge B1 and thus make it responsive to any desired pitch. These parts all form a water* tight chamber t0 one side of the casing, which otherwise would be open.

Upon the diaphragm D is mounted the microphone G by means of a stem g' in the usual way, the microphone being in the chamber a and its stem g passing outwardly through the opening a3. A `neck H at the top edge ot' the casing has a stuffing box of ordinary construction (not shown) through which pass out the microphone leads d, d, which pass from the casing and preferably through a rubber tube a4 located therein to centre and protect them.

From the chamber a projects downward a passage K having a test opening 7i: closed by a plug This passage K is connected with a collapsiblemember K1 by a watertight coupling which as shown comprises a short metallic pipe L threaded to sc rew into the casing and enlarged at its outer end and properly shaped to have drawn over it the open end ot' the collapsible member K1. The coupling proper comprises a clamping sleeve L1 and nut L2.

As shown the collapsible member K1 comprises a rubber tube the lower end of which is sealed to make it both watertight and airtight, and all the joints of the device are made watertight and airtight so that the device is practically sealed, and under these circumstances of course the collapsing in any way of the collapsible member K1 will result in the compression ot the air contents of the device.

in practice, when this device is hung overboard in the water the collapsible member K1 will bc collapsed by water pressure, but the pressure on the collapsible member K1 will compress the air inside the device and, being the same as the pressure on the diaphragm D, the two will equalize each other it the parts are properly proportioned so whichy ring sald diaphragm that the'device may be considered self-equalizing in every respect, the pressure on the two sides of. the diaphragm being at all times equal. Thus the pitch of the diaphragm Will in no Wise be changed, nor Will it lose its effectiveness because of any unequal pressure upon its tWo sides.

I 'do not mean to limit myself to the precise form of my invention shown as other forms thereof Will occur to those skilled in the art.V Y The ,collapsible member vshown may be dierently shaped and constructed and insteadof air other gas may be used if desired. Moreover, as a pressure neutral# izer my method is equally efective Whether used With a tuned or untuned diaphragm.

What I claim as my invention is 1. A microphone instrument, for submarine use, comprisin body casing parts Within which is a cham er, a circular bridge` on one of said body parts, a diaphragm so mounted as to form one side of Said chambei` and render the same Water-tight, a microphone mounted at one side of'said diai phragm in said chamber, a hollow collapsible member serving as an air container and the chamber of which member communicates with the said water-tight chamber, a ring secured to a body part of the device and by is tightly clamped toa body part to make a Watertight joint, and an adjustable tuning ring bearing against said diaphragm inside of said first-named ring and outside of said circular bridge. l A

2. A microphone instrument, for submarine use, comprising body casing parts within which is ai'chamber, one of said body parts having a circular projection affording a bridge over which said diaphragm is stretched, a 'diaphragm so mounted as to form one side of said chamber and render the same Water-tight, a microphone mount- /ed at one side of said diaphragm in said chamber, a hollow collapsible member serving as an air container and the chamber ot Which communicates With the said Water y tight chamber, a ring secured'to a body part of the device and b which ring said diaphragm is tightly c amped to a body part to ymake a Water-tight joint, an adjustable tuning ring bearing against said diaphragm inside of said first-namedl ring between said circular bridge and the clamped edge of said diaphragm, and leads or conductors extendingfrom said microphone to the outside of said casing parts through a Water-tight passage.

EDVARD C. WOOD.

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