US2410454A - Voice-transmitting gas mask - Google Patents

Description

Nov. 5, 1946. A. V. MOT$|NGER 2,

VOICE-TRANSMITTING GAS MASK v I Filed May 17, 1938 ,3 Sheet-Sheet 1 IN VEN TOR.

' Armand VMotsiny BY Y A ATTORNEY 1946. A. v. MOT SINGER VOICE-TRANSMITTING GAS MASK I Filed May 17, 1958 V 3 Sheets-Sheet 2 INVENTOR. Armand VMotgi n A TTORNEY Nqv. 5, .1946; A. v; MOTSINGER VOICE-TRANSMITTING GAS MASK 5 Sheets-Sheet 3 Filed May 17, 1938 FIG. .9 1-76. /0

IN V EN TOR. A rm and. V- Motsinyer M A TTORNEY Patented Nov. 5, 1946 UNITED STATES PATENT OFFICE VOICE-TRANSMITTING GAS MASK Armand V. Motsinger, near Aberdeen, Md. Application May 17, 1938, Serial No. 208,408

12 Claims. (01. 128-141) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by and for the Government for governmental purposes, without the payment to I me of any royalty thereon.

This invention relates to voice-transmitting gas masks and has for an object to provide a gas mask through which a person can talk without the use of electrical or other outside energy.

Another object of this invention is to provide a diaphragm which will readily transmit the human voice.

Another object of this invention is to provide a sound box or acoustical chamber next to a diaphragm in order to increase the transmission of speech through the diaphragm.

Another object of this invention is to provide a sound box or acoustical chamber that is adjustable so as to conform to the individual voice of the wearer of a mask or to the sound characteristics of a given mask.

Another object of this invention is to provide a facepiece of a gas mask with diaphragms and acoustical chambers on either side of the facepiece which may respond to different sound frequencies.

With the foregoing and other objects in view, the invention consists in certain novel features of construction and arrangement of parts as will be more fully disclosed in connection with the accompanying drawings.

In the drawings:

Fig.1 is a sectional view on line I-l of Fig. 2 of a facepiece of a gas mask in place on the face, showing th position of the acoustical chamber and diaphragm.

Fig. 2 is a front view of a facepiece, in place on a mans head, showing the diaphragm in the front part of the facepiece.

Fig. 8 is a front view of a facepiece, in place on a mans head, showing angletubes with diaphragms on the side of the facepiece.

Fig. 4 is a front view of an angletube of a facepiece showing deflectors in the acoustical chamber and position of the diaphragm.

' Fig. 5 is a section on line 55 of Fig. 4 showing a diaphragm and acoustical chamber with sound deflectors.

Fig. 6 is another variation of angletube having an acoustical chamber. It shows the acoustical chamber with holes around the edge for entrance of sound.

Fig. 7 is a sectional view on line 1-! in Fig. 6.

Fig. 8 is a front elevation of an angletube showing an adjusting device for changing the sound characteristics of the acoustical chamber.

Fig. 9 is a cross section on line 9-9 of Fig. 8 showing an acoustical chamber which can be varied in shape and size to respond to various voice characteristics.

Fig. 10 is a rear elevation of the angletube with adjustable chamber shown in Figs. 8 and 9.

Corresponding and like parts are referred to in all the views by like reference characters.

A diaphragm when transmitting speech does not resonate at one frequency but must vibrate in therange of frequencies corresponding to the voice range. The kinetic energy must be overcome at each cycle and since the power available in the voice is low, the kinetic energy of the diaphragm must be low. Therefore the diaphragm must be as light in weight as possible. For use in gas masks the diaphragm must be mechanically strong and of a material to prevent the passage of gases.

In accordance with this invention the diaphragm is formed. of a plurality of separate plies of material secured together only at their peripheries. Diaphragms made of cellulose derivative such as Cellophane, cellulose nitrate, or cellulose acetate, have been successfully used,

with two to five plies. Preferably four plies of cellulose acetate are used, each ply about one thousandth of an inch thick, as this assembly ,afiords mechanical strength, impermeability to gases, resistance to deterioration, and vibration range to accommodate the human voice. A sufficient number of plies must be used to prevent chatter.

Voice diaphragms of individual plies secured only at their edges have a very small energy loss since the separate plies may vibrate individually. A diaphragm made in this way has no undesirable resonance since the separate lamina dampen the adjacent lamina.

Gas mask facepieces are usually formed of flexible material to conform closely to the wearer's face. In order to avoid a plurality of connections to the facepiece, it is common practice to provide one rigid member formed of metal, which is connected to the facepiece and by which the air enters and leaves the facepiece. This member, which also serves to hold the facepiece in shape and prevents collapsing due in inhalation, is known in the trade as an angle tube and is so designated herein.

Referring to the drawings, the plied diaphragms H formed of a plurality of plies of cellulose derivative is secured at its periphery against a gasket 12. From Figure 1 it will be noted that an angle tube [4 is suitably secured in a gas-tight manner to the flexible facepiece [5, has an undercut annular flange l6 against which gasket [2 is pressed. Diaphragm l I and gasket l2 are secured in place by a crimped rim ll of the metal acoustical box i8. Acoustical box i8 is a cup-shaped member with its rim progressively decreasing in depth from (the upper to the, lower portion, as seen in Figure 1. The bottom of box 18 has a plurality of openings i9 arranged adjacent the upper portion and in front of the wearers mouth.

The gasket I2 engages against a beveled surface on flange IS, the arrangement being such that as the rim i1 is crimped in place and as'pressureis applied to diaphragm l I the gasketi 2 is displaced outwardly to thus evenly stretch the diaphragm. Since there is not twisting action in stretchin the diaphragm, there is no tendency to wrinkleor break the thin diaphragm.

A rubber outlet valve 2! may be secured to an outlet nipple 22 on the angle tube Hi, and an inlet *hose to inlet nipple-38. It has been found that the sizeand shape of the acoustical chamber ior-m'ed by a box l8 aiiects the sound transmitted through the diaphragm, and the shape and size ofthe chamber varies for different voices. For

average voices, the back or bottom of chamber 18 should be placed at an angle of to the diaphragm ll.

Voice transmission may be further improved 'by'bafiles within the acoustical chamber. As seen in Figs; 1,4 and 5, a baifie 23 having-a curved upper'edge to engage the acoustical box extends downwardly'-at an angle of about 42 to the base orback 48 of the'box. I Two side bailles 28 of sub- -stantial1y triangular shape extend from bafiie 23 -downwardly atabout 65 to baifie 23. Bafiles 23 'and idj justclear'diaphragmil to allow free vibration thereof.

The openings l9 andbafiles 23 and24 concentratethe voice sound waves to the center of the diaphragm, thus increasing the efiiciency of sound transmission.

In Figs. Sand '1 is'shown another shape of acoustical chamber. In this form the back 25 of ;the acoustical chamber is in the shape of a cone, with the inner point out of engagement with diaphragm H. The side of the cone makes an angle of about 15 to the diaphragm. Sound enters the chamber through openings 26 in the cone.

Thisfchamber is also crimped to the angle tube [to secure the diaphragm in place, as previously described, the acoustical chamber being on the inside of the facepiece.

since th type of voice andthe interior cavity ofthe iacepiece affect'the sound transmitted by --sui-tably secured to a metal cup 28 which in turn secures the'diaphragm ii to the angle tube. By

-m'oving the back 21 in or out, the size and shape of the acoustical chamber may be varied to suit 'the-voice of the wearer. In the open'extended position of the back, the acoustical chamber will foest fita tenor voice, whereas in the depressed position the chamber will best fit a bass voice.

"Resilient back 21 has a series of holes 29 around its periphery through which sound enters the chamber.

The resilient back 21 may be adjusted by a thumb, screwtf threaded to a strap 32 on the 'jangIe'tube; the inner endoi the thumb screw arranged to press the flexible facepiece'material l5 4 against a bell crank 33. Crank 33 is pivoted at 34 to the angle tube, and its inner end engages the resilient back 21. Thumb screw 3| may have a numbered dial for cooperation with a mark 35 on the strap 32.

Two angl tubes with diaphragms and acoustical chambers may be mounted in ",the; cheek portions of the facepiece as seen in Fig. 3. -One angle tube 36 may have its acoustical chamber arranged to respond more eificiently to a tenor voice, the

. ,other. angle tube 31 to a bass voice, thus giving a widerrange of voice transmission without re- ;sorting' to ;an adjustable acoustical chamber.

The optimum size and shape of the chambers for a certainshape of facepiece may be determined by -talking tests or by impressing known sound waves within the iacepiece at various frequencies and measuringthe sound transmitted through the diaphragms.

It will be understood that the invention is not limited tothe precise details herein shown and described by .way of illustration, since many changes and variations may' be made therein by those skilled in the art without departing from the-spiritoi the invention nor exceeding the scope of the appended claims.

' I claim: 7

1. A voice transmitting gas mask comprising a iacepiecaand a diaphragm therein in voice transmitting relation to the mouth of the wearer, said diaphragm formed of a plurality of layers of thin gas-resistant material'secured together only at men edges and stretched taut.

' 2. The invention as defined in claim 1 wherein said diaphragm is formed of a plurality of layers of a cellulose derivative.

3. The invention as defined in claim 1 wherein said diaphragm is formed of a plurality of layers -cf cellulose acetate.

4. In a voice transmitting mask, a sound box having a perforated bottom, an angle tube, a diaphragm formed of a plurality of plies of cellulose derivative positioned between said sound box and angle tube, and means to secure said sound box and angle tube together and simultaneously stretch said diaphragm, said plurality of plies beingsecured only at their edges.

5. A voice transmitting gas mask comprising a 'fa'cepiece, an annular cup-shaped angle tube 'secured therein, a voice-transmitting diaphragm closing said angle tube, said' diaphragm being formed of a-pluralityof separate layers of-material secured together only at their edges, said angle tube having an annular lip having adiaphragm engaging surface at an angle to the :plane ofwthe diaphragm, saiddiaphragm-being pressed 'againstsaid surface to thereby stretch the diaphragm.

6:, Th invention as'defined in claim- 5 wherein asound box is secured to said angle tubewithin the facepiece to concentrate sound waves on the diaphragm.

5'7. Acvoice transmitting gas mask comprising a facepiece, an angle tube secured therein, a diaiphragmiormed of a plurality of plies of gas- ."impermeable material, means to secure said' diaphragm across said angle tube, said -means securingsaid diaphragm only around its edge, and a sound amplifying box on theinside'of said facepie'ce forming a chamber having a perforated bottom, said bottom being positioned at; an angle to the diaphragm.

i 18 The invention asdefined inclaim 'l wherein Said am i s b Lh S b tber inslorin toward" the center of the diaphragmwhereby voice waves are concentrated toward said center.

9. The invention as defined in claim 7, wherein cooperating means are provided on the angle tube and amplifying box to secure these members together, said cooperating means also securing and stretching said diaphragm.

10. The invention as defined in claim 7, wherein said diaphragm is formed of three to five plies of cellulose acetate.

11. A voice transmitting gas mask comprising a facepiece, an angle tube secured therein, a diaphragm formed of a plurality of plies of gasimpermeable material, means to secure said diaphragm only around its edge, and a sound amplifying box on the inside of said facepiece, said box having closed side walls and a perforated bottom, said bottom being readily adjustable toward and from the diaphragm to thereby adjust the size of the sound box to the voice.

12. A voice-transmitting assembly for gas masks, comprising in combination, an angle tube, a sound amplifying box joined to the angle tube at one side of the latter, coacting means on the angle tube and on the sound amplifying box providing a joint therebetween, a diaphragm secured within the confines of said joint with the marginal edge only of said diaphragm being clamped between the coacting means on the angle tube and sound amplifying box, and said sound amplifying box having a wall adapted to be flexed toward and away from said diaphragm, and means accessable at the side opposite the sound amplifying box for adjustably flexing said wall.

ARMAND V. MOTSINGER.

of the angle tube

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