GB2165721A - A speech facility for a facemask - Google Patents

Abstract

A method and apparatus for imparting a speech facility to a face mask or the like in order to reproduce outside the mask the voice of a wearer. Electronic circuitry 31 is employed in conjunction with a microphone 35 and a speaker 25 to reproduce the voice of the wearer. By using electronics incorporating an amplifier, the desired output sound level can be achieved without the need for the wearer to shout. The electronic components are accommodated within an airtight casing 21 which is adapted to be secured to the mask in an airtight manner. An airtight membrane 27 is provided over the speaker and forms part of the airtight casing. In one embodiment the microphone 35 is disposed within the face mask and connected to the electronics by wires. In another embodiment, the wearers voice is communicated to the microphone by way of a sound transmission tube which extends from the apparatus into the face mask. <IMAGE>

Description

SPECIFICATION A speech facility for a face mask I he present invention relates to speech facility for use in industrial, commercial or military breathing apparatus, face masks, gas masks or respirators or any safety helmet where speech is impaired.

A known method of speech transmission in face masks used in irrespirable atmospheres is similar to thatshown in Figure 1 and 2. Figure 1 shows a compressed air breathing apparatus face mask 1 having an inner oral-nasal mask 3 and speech facility apparatus 5. The speech facility apparatus is shown in further detail in Figure 2 which is a cross-section through the apparatus. It comprises a conical housing 7 which is attached to the mask 1 by a screw threaded fitting 9. Insidetheconeand stretched overthewide end thereof is an airtight plastic membrane 11, this air tight membrane is protected by a perforated nylon cover 13.The sound istransmitted to the outside ofthe mask by sympathetic vibration of the plastic membrane 11 when the mask wearer speaks.This produces a distorted and poor sound quality, which the speaker hastoovercomebyshouting.Thisputsan unneces sary strain on the mask wearer and is not an efficient way of communication when wearing face masks in hazardous or strenuous conditions.

It is an aim of the present invention to provide a speech facility for a face mask which avoids the above mentioned problems of the known apparatus, and which does not give rise to any operating restrictions.

The present invention provides a method of imparting a speech facility to a face mask orthe like using an electronic circuit in conjunction with a battery mic rophoneandspeakerto reproduce the wearer voice from inside the mask to the outside.

Conveniently, the components are incorporated in a miniaturised assembly. More specifically the electronic circuitry incorporates an amplifier. The method enables the speakers voice to be reproduced outside ofthe mask without distortion or loss of volume, thus enabling the wearerto be clearly and audibly understood with the normal effort of speech.

According to the invention there is provided apparatusfor use with a face mask orthe like for imparting a speech facility to the mask, comprising an electronic circuit and a battery, a microphone and a speaker to reproduce the wearers voice from inside the mast to the outside.

The apparatus is conveniently incorporated in a miniaturised assembly and is readily adapted to be fitted to the face mask by way of a screw threaded connection. The screwthreaded connection enables the apparatus to be completely detachable from the face mask. The electronic circuit incorporates an amplifier. Alternatively, the apparatus may be provided as an integral part of the face mask, thus avoiding the need forthe screwthreaded connection.

Thevoiceoftheweareris picked up bythe microphone and converted into an electronic signal by the electronic circuitry and then to an audible signal by the speaker. The audible outputfrom the speaker may be employed to vibrate an airtight membrane placed overthe speakerorthe speaker membrane itself may constitute the airtight seal. In one embodiment, the microphone is placed in the mask and preferably penetrates the oral-nasal mask. The electronic circuitry incorporates an amplifier and the resulting signal is relayed to the speaker and transmitted to the outside of the assembly through an airtight seal. Wires connectthe microphoneto the electronic circuitry.

Conveniently, the wires from the microphone are disposed within a screening tube. The wires pass through the centre orifice ofthe screwthreaded connection and atthis point are surrounded by an air tight sound absorbing bung.

In a second embodiment, the microphone is disposed within the housing ofthe apparatus and sound from the wearer is transmitted to the microphone by way of a sound transmission tube. This passes through the screw threaded connection and leads into the mask and preferably into the interiorofthe inner oral nasal mask. Sound travels down the tube to the microphone and the signal generated from the microphone is amplified by the electronic circuit, relayed to the speaker and transmitted to the outside of the assembly through an airtight seal.

The use of an amplifier enables thewearerto speak in a normal voice, whilst allowing a sufficiently high output two be generaled to make output signal clearly audible. A battery is provided to provide the power sypplyto operate the amplifier.

The present invention will now be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 3 illustrates a face mask incorporating a speech facility apparatus according to afirst embodiment; Figure 4is a partially broken awayviewofthe speech facility apparatus of Figure 3; Figure 5 is a cross-section through a speech facility apparatus according to a second embodiment; and Figure 6 is a circuit diagram of a typical electronic circuit for use with either of the embodiments of Figures 4 and 5.

Referring firstly to Figures 3 and 4, there is illustrated a first embodiment of apparatus for impart- ing a speech facility to aface mask. The face mask is generally identified as 15 and incorporates an inner oral-nasal mask 17. The speech apparatus is identified bythe reference numeral 19 and is shown in further detail in Figure 4. It comprises an airtight casing 21 which has a threaded connection 23 for mating with a correspondinglythreaded hole in the face mask 15.

This may be a hole already provided in the maskfor receiving a sympathetic vibration type of speed transmission device as described with reference to Figures 1 and 2, or it may be provided specificallyfor use with the apparatus of the present invention. The connection with the mask incorporates a seal to maintain the airtight integrity of the face mask.

A speaker 25 is disposed within the casing 21 and it is covered by an impervious membrane 27 which The drawing(s) originally filed was(were) informal and the print here reproduced is taken from a later filed formal copy.

provides an airtightseal.The impervious membrane 27 is covered by protective cover 29 which is conveniently provided with perforations. Also disposed within the casing is the electronic circuitry 31 which incorporates an amplifier, an on-off switch 33 for activating and deactivating the apparatus electronics, and a battery 32 providing a source of powerfor the electronics.

A remote microp5qcne 35 is connected to the electronics ofthe apparatus by wires 37. The wires are preferably disposed within a screened tube 39. The wires pass out from within the casing 21 byway of a sleeve 41. The exterior ofthe sleeve carries the screw threaded connection 23. An airtightsound absorbing bung 43 is disposed within the sleeve and the wires 37 and the screening tube 39 pass through this bung. The bung preventsthetransmission ofunwantedsound waves between the interior of the mask and the rear face ofthe speaker cone.

Figure 6 illustrates an electronic circuitfor use in the apparatus of Figure 4. The output from the microphone 35 is operated on to produce an output signal to drive the speaker 25, i.e. the circuit amplifies the signal from the microphone and relays them to the speaker. Naturally, alternative circuit designs may be used to achieve this objective.

Referring now to Figure 5, there is illustrated a cross-section through an alternative embodiment of apparatus. Like reference numerals have been used to denote the parts corresponding to those used in Figure 4. The apparatus is similarto that illustrated in Figure4but hasthe remote microphone replaced by an internal microphone 35' and a sound transmission tube 51 is employed to convey sound from the mask wearertothe microphone. The sound transmission tube conveniently leads into the inner oral-nasal mask. The microphone 35' is conveniently disposed within the sleeve 41 which incorporates an air tight bung 43 to prevent the unwantedtransmission of sound between the interior ofthe mask and the speaker.The apparatus also accommodates, within the airtight case 21 the electronics 31 and the battery 32 providing the source of power. A switch 33 is provided for activating and deactivating the electronics. The switch 33 projects from the casing, within which it is mounted sealingly, so asto be operable externallybythewearerofthe mask. An airtightseal is provided overthespeaker25 byan impervious membrane 27. This is protected by an external end cover 29 which is conveniently perforated. The casing is generally cylindrical and the centre line of the sleeve 41 is conveniently offset from the axis ofthe casing.

However, this is not essential and the two axes may be coaxial. Othershapesand configurations may be employed and the housing of the apparatus mayform an integral partofthe mask.

The circuit diagram described with reference to Figure 6 is suitablefor use in eitheroftheembodi- mentsofFigure4and 5.The various components of the electronics are conveniently secured to a printed circuit board. This board conveniently takes the form of one half of a.1 annulus. The apparatus is powered by a 9volt battery supply.

The electronic speech facility works as follows. In the caseofthe first embodimentthe voice ofthe wearerispicked up bythe microphone35 which is placed in the mask and penetrates the oral-nasal mask (Figure 3) and relayed to the speech facility assembly (Figure 4) and amplified by the electronic circuit (Figure 6), relayed to the speaker 25 and transmitted to the outside ofthe assembly through an airtight seal 27.The electronic circuit (Figure 6) has the capability of being reduced in size and the whole assembly, circuit or components, being altered in size, shape and layout accordingly, but the principal ofthefacility remaining the same, an electronic assembly as described, as an integral part of a face mask to reproduce the wearers voice from inside a mask to the outside, the assembly can also be adapted to fit any face mask by altering the means of securing the facility to the mask being used.

This speech facility will satisfy any criteria for gas tightness, water/acid/alkali resistance and intrinsic safety and would satisfythe rules governing the construction and use of breathing apparatus as laid down by the Home Office.

In the case of the second embodiment, the voice of the wearer is transmitted down the sound transmission tube 51 to the microphone 35' which transmits a signal to the electronic circuitry 31 where, when the electronics are activated by operation ofthe switch 35, the signal is amplified and drives the speaker 25. This causesthe airtight membrane 27 to vibrate in sympathy so generating an externally audible sound.

The use of electronics incorporating an amplifier enables a clearly audible sound to be generated withoutthewearerofthe mask having to shout.

The described embodiment of apparatus can be detached from the maskforservicing and when attached requires no special operating procedures or restrictions for the operator except four switching the apparatus on and off. Nor is there any loss oftime in donning the apparatus.

It is preferred that the microphone or the sound transmission tube extend into the inneroral-nasal mask but this is not essential. The microphone may be positioned in the sleeve and the sound transmission tube omitted in certain circumstances.

Claims (13)

1. Apparatus for use with a face mask orthe like for imparting a speech facilitytothe mask,comprising an electronic circuit and a battery, a microphone and a speaker to reproduce the wearers voice from inside a masks the outside.

2. Apparatus as claimed in claim 1 in which the electronic circuit includes an amplifier.

3. Apparatus as claimed in claim 1 or 2 in which the apparatus comprises a housing which is adapted to be releasably and sealinglysecured to a face mask by connection means.

4. Apparatus as claimed in claim 3 in which the connection means comprises a screw threaded connection.

5. Apparatus as claimed in any of claims 1 to4in which the microphone is disposed within the face mask and connected to the electronics by wires.

6. Apparatus as claimed in any of claims 3 or4 in which the microphone is disposed within the housing.

7. Apparatus as claimed in claim 6 in which the wearers voice is communicated to the microphone by a sound transmission tube which leads into theface mask from the microphone.

8. Apparatus as claimed in any preceding claim in which the speaker is covered by an airtight membrane which is vibrated in sympathy with the speaker.

9. A method of imparting a speech facility to a face mask orthe like using an electronic circuit in conjunction with a battery, microphone and speaker to reproduce the wearers voicefrom inside the maskto the outside.

10. A method as claimed in claim 9 in which the wearers voice is amplified by the electronic circuit to drive the speaker and generate a clearly audible sound and wherein the sound from the speakersets up sympathetic vibration in an airtight membrane covering the speaker.

11. Aface mask orthe like incorporating integrally therewith apparatus for imparting a speech facility to the mask comprising an electronic circuit and a battery, a microphone and a speakerto reproduce the wearers voice from inside a mask to the outside.

12. Apparatus constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing of Figure 3 and 4 or 5.

13. A method of imparting a speech facility to a face mask orthe like substantially as hereinbefore described with reference to the accompanying drawings of Figures 3 to 6.