US1297206A - Means for detecting sounds. - Google Patents

Description

D. MCLENNAN.

mums FOR 0512mm sounms.

APPLICATWN FILED OCT-13,1917.

Patentsd; Mar. 11', 191%.

DUNCAN MCLENNAN, OF CROYDON, ENGLAND.

MEANS FOR DETECTING SOUNDS.

Specification of Letters Patent.

Patented Mar. 11., 1919.

Application filed October 13. 1917. Serial No. 196,548.

To all whom it may oncern.

Be it known that I, Dr'xcax McLnxxax. a subject of the King of Great Britain and Ireland, residii'ig at Croydon, in the county of Surrey, England, have invented Improvements in ll leans for Detecting Sounds. ot' which the following is a speciti 'ation.

This invention relates to compound diaphrag'ms for use in or with somul-trans n'iitt-ing and s m1ul-receiving instruments or apparatus such as telephones phonographs, stethoscopes, signaling instruments and the like.-

A compound diaphragm arrangement according to the present invention comprises coaxial diaphragms mounted parallel to one another so as toform between them a closed space that is charged with liquid, the diaphragms being of different effective diameters and maintained apart at their peripheries by interposed peripheral distance pieces so to insure their being kept parallel one to= another, the central portion of the closed space between them being always free except for the contained liquid. More than two diaphragms may be thus arranged to form two or more spaces that are filled with liquid. With such an arrangement, the vibrations are rendered dead-beat by the liquid. Furthermore, when the two or several diapl'iragms are of different sections or thicknesses, and therefore of different periodicity values, the range of notes to which the combination will respond is considerably augmented.

Such a compound diaphragm arrangement with parallel diaphragzms and inter posed liquid, may be cmploytal generally in or with soimd-transmittino and soundreceiving instruments or apparatus.

The distance or distances between. the elementary diaphragms should be small compared with the diameters of the diaphragms or at least compared with the diameter oi the larger or largest diaphragm it the diaphragms diti'er greatly in diameter.

hen this compound or combination diaphragm arrangement is applied say to a telephone transmitter. the microphone would be attached to one side and the air vibrations or waves caused by the voice would act on the other side.

Similarly, in the case of say a telephone receiver, the magnet poles would l applied to one side of the combination diaphragm a d the listeners ear placed near the other.

Any suitable liquid may be used between the diaphragms. A liquid suitabletor the purpose is a. mixture of distilled water and glycerin.

In the accompanying drawings, Figure l is a face VlCW and Fig. 2 a section on the line 2; of Fig. 1 showing: one example of a compound diaphragm arrangement having elementary diaphragrms ot' ditterent ctt'ective diameters with liquid chamber according to the invention. Figs. 3 and are similar views of another example o't'.a compount diaphragm according to the invention.

The compound diaphragm arrangement. shown in Figs. l and 2 comprises two circular metal diaphragms a and o secured to the opposite sides of a ring 0 recessed so that the efi'ective portions of the two diaphragms secured to its opposite sides are in ett'ect of different diameters for the purpose hereinbefore explained. The ring may be of any suitable material, metallic or non-metallic, for example vulcanite, so as to form therewith a closed chamber that is charged with liquid (ll. For the latter purpose the ring 0 may also be formed with two oppositely arranged holes 0 and f for exit of air and inlet of the liquid. these holes being afterward hermetically closed, as for instance by screws g, or caps. In this example the two diapliraems a and I) are shown as of unequal thickness.

The closed chamber may be completely tilled with liquid or only partly tilled. When the ring (2 is of metal the diaphrae'n'is a and 7) may be secured thereto in a tluid tight manner as by soldering the parts together, or in any case the diaphragn'is and interposed ring, whether of metal or other material, may be clamped together bet-Ween outer rings a, as by screws passing through the assembled parts.

in the compound diaphragm arrangement shown in 3 and 4 there are three diaphragms a, 7) and I1 clamped in place within a holderz' by rings j, and m respectively which may be. screwed into the holder '11, as shown, in be otherwise held together so as to form two interposed chambers charged with liquid (Z.

As will be readily undcrstoml, compound diaphragm arrangements such as described can be used in ('(JlliltttlOl'l with apparatus of various kinds, some of which have hereinbetore been indicated, designed for the trans mission, reproduction or detection of sounds,

olccta'iouliy or otherwise. One ugpiication of s11 a sompoxmd dt uphz'agm uri'amgvnzont is; cribud in the :spocii Lion of another application for otters Pun-m mod (13th @miobcr 1917) by me ("MLifll No. 2965 or uso in common! ioo with sound dmovting upprv mtus. @Hmi uses will brrozuiiLy understood Without further oxplzumiion.

11M (whom is1--- 1. A. sound hmmniffing or wwiving compound dinphm =11 ommgrising: (Uuphrugms zuirungod in 211103 to (nu-n other, moans for uonneoting tho poi'iphvl'ul portions of said diaphmgms and liquid inclosod Within the space im'n'md by said dinphmg'ms the pox tion of {he dizxphrngms oxnosod to the liquid being; of difi'omnt vfi'eci'ivo arm.

A sound 'nwmsmii'iiing 0! receiving; compound diaphragm uompl'ising filamentary diaphragxns 1110:1115 of (HEM-on! Miami: widti'xs e-ximiding ilm'm'dly from 131c com mon pvriphmios of and iv f om with said 9 ommfi m ans vori'esponm 7 effoofive diameters ,0 his )h 1155 and forming a and liquid imiosod Within he an id :liupm'agm snbsmn! izaily as 3. sounn mnsmitt pound diaphz z wherein the 01 nnoqunl 'thioim A compound din as claimed in claim us with info hem portums mil-s of between r as doscribeo.

Q or subs-taut sawed 6. A Sound f h, 1 .1. I) UDEJL FL 7

Images