Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3180333 A
Publication typeGrant
Publication dateApr 27, 1965
Filing dateMay 29, 1963
Priority dateMay 29, 1963
Publication numberUS 3180333 A, US 3180333A, US-A-3180333, US3180333 A, US3180333A
InventorsDavid Lewis Robert
Original AssigneeAcme Prot Equipment Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Gas mask communication system
US 3180333 A
Abstract  available in
Images(3)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

April 27, 1965 R. D. LEWIS 3,180,333

GAS MASK COMMUNICATION SYSTEM Filed May 29, 1963 3 Sheets-Sheet 1 April 27, 1965 R. D. LEWIS 3,180,333

GAS MASK COMMUNICATION SYSTEM Filed May 29, 1963 3 Sheets-Sheet 2 z M d/ 2 Ways April 7, 1965 R. D. LEWIS 3,180,333

GAS MASK COMMUNICATION SYSTEM Filed May 29, 1963 3 Sheets-Sheet 3 United States Patent 3,180,333 GAS MASK COMMUNICATION SYSTEM Robert David Lewis, Eoloma, Mich, assignor, by mesne assignments, to Acme Protection Equipment Co., South Haven, Mich, a corporation of Michigan Filed May 29, 1963, Ser. No. 284,179 Claims. (Cl. 128-141) This invention relates to a gas mask communication system, and more particularly to the means for adapting gas masks for amplification of the wearers voice. The invention also relates to a holder for electrical components of a voice amplification system adapted for use in combination with a gas mask.

It has heretofore been proposed to equip gas masks with voice amplification means whereby the wearer of the mask can communicate with other gas mask wearers, or with control personnel not wearing masks, as may be required when persons at least some of whom are wearing gas masks must cooperate on an industrial or military project. However, in adapting gas masks for voice amplification a number of problems are encountered. For example, it is undesirable to provide attachments for gas masks which intercfere with the visibility of the wearer, or which tend to restrict or hamper the freedom of movement of the wearer. An accessory or attachment protruding outwardly from the side or front of a gas mask can be cumbersome, and may have a tendency to cause the mask to separate from the face of the wearer, thereby causing the gas mask to leak. With delicate electrical components, such as those required for a voice amplification system, it is extremely difiicult to provide a mountng which avoids the problems discussed above while at the same time adequately protecting the electrical components. Heretofore, these interrelated problems have not been satisfactorily solved, and this has greatly restricted the acceptance of voice amplification means for gas masks, although there is a need for such amplification under many conditions of industrial and military use.

It is, therefore, an object of the present invention to provide a gas mask communication system which substantially overcomes the problems and diiiiculties described above and which for the first time provides a fully satisfactory means for adapting gas masks for voice amplification. Further objects and advantages will be indicated in the following detailed specification.

The gas mask communication system of this invention is illustrated in the accompanying drawings, in which FIGURE 1 is a perspective front view illustrating a gas mask equipped with the communication system of the present invention as it might be worn by a user thereof;

'FIGURE 2 is a fragmentary vertical sectional view taken on line-2-2 of FIGURE 1;

FIGURE 3 is a front elevational view of the detache holder;

FIGURE 4 is a top viewof the detached holder with portions broken away to show the internal components and other internal components being shown in phantom; FIGURE 5 is a fragmentary vertical sectional view taken on line 5-5 of FIGURE 4;

FIGURE 6 is 'a bottom view of the gas mask combination of FIGURE 1 taken on line 6-6 thereof and showing particularly the mounting of thebolder containing electrical components of the voice amplification system; and

FIGURE 7 is a circuit diagram for the electrical com- .The face piece will usually be formed of a flexible im- 3,11%,333 Patented Apr. 27, 1965 pervious material such as natural rubber or other elastomeric material. The outer peripheral portions of the face piece are adapted to conform closely to therface of the wearer, and there is usually provided a chin-conforming portion 12, as shown more clearly in FIGURE 2. Means is also provided for holding the face piece securely on the head of the wearer. In the illustration given, a plurality of adjustable head straps 14 are provided for this purpose.

In accordance with the usual practice, the gas mask is provided with window means to provide maximum visibility for the wearer. In the illustration given, two viewing windows or lenses 13 are provided. If desired, a single viewing window can be used. With the construction shown in FIGURE 1, a flexible strip 11a extends between the windows to permit the further adjustment of the mask to the face of the wearer. Usually, the face pieces of the masks are molded from rubber or other suitable flexible, elastic material.

The gas masks of the kind with which the present invention is adapted to be employed have their lower portions equipped with one or two outwardly-extending tubular extensions which provide air passage means, such asan air inlet, an air outlet, or both an air inlet and an air outlet in one extension. In the illustration given, the tubular extension is indicated generally by the number 15. This can be seen in FIGURES 1 and 2. The-extension projects outwardly and downwardly from the lower portion of the face piece 11 over the chin-conforming portion 15. Extension 12 provides passage means therein, such as the passage 16, for supplying air to the face of the wearer. The passage 16 can be connected to a suitable conduit 17, which, in turn, is connected to a source of compressed air or to a suitable gas mask canister into which air is drawn from the surrounding atmosphere. It will be understood that this invention is not limited to the particular type of tubular extension and air passage means shown. For the purpose of the present invention, it is desirable that the tubular extension 15 be at least semirigid and substantially less flexible and yielding than face piece 11.

If desired, the tubular extension 15 can also provide an air outlet passage, the inlet and outlet passages being concentrically arranged as with the gas mask of FIGURE 1. The concentric passage arrangement is shown more clearly in FIGURE 2, the outer concentric passage which provides the air outlet passage being designated by the number 18. In the illustration given, the tubular portion 19 is integrally formed with the face piece 11. Within tubular portion N there is received a unitary member which includes an outer ring 29 and an inner tube 21 rigidly interconnected by web members 22. retainer or clamping ring is received over the outside of tube 19 to assist in locking ring 20 in place. The tubular portion 19 terminates in an outer lip 24 which cooperates with a flexible diaphragm valve 25 as received'on tube 21. The construction and operation of the concentric inlet and outlets and valve means therefor is described more fully in Patent 2,684,006. Details thereof are not directly connected with the present invention.

As will subsequently be described, the tubular extension, such as extension 15, provides the means for mounting a holder of special construction on the mask, and therefore it is desirable, as already indicated, to have extension 15 sufficiently rigid for this purpose. In the particular illustration given, although tubular portion I9 is formed of flexible material, increased rigidity is supplied by the member providing the ring 20 and tube 21 and the clamping ring 23. Ring 23 can conveniently be formed of metal or plastic, while the inner member which provides the ring 29 and the tube 21 can be molded from a suitable plastic as a one-piece integral unit.

In accordance with the present invention, there is provided a holder for electrical components of a voice amplifier system which is detachably mounted on the tubular extension of the mask. In the illustration given, the holder is designated generally by the number 26 and is shown as detachably mounted on the extension 15. As shown more clearly in FIGURES 3, 4, and 6, the holder 26 is characterized by a tubular housing having a generally rJ-shaped configuration. The housing includes arm portions 2"? and 28 and a base portion 2?. As shown in FIGURES 1 and 6, the base portion 29 of the holder receives the underside of the extension and the'arms 27 and 23 of the U extend outwardly around the tubular extension.

In accordance with the present invention, means is provided for detachably mounting the holder 26 on the extension 15 in the relation just described. For example, there can be provided a strap clamp means which extends between the arms 27 and 28 over the upper side of the extension 15. Preferably, the strap means is releasable or elastic so that the holder can be easily applied or detached. In the illustration given, there is shown an expandable spring 33 which has its outer ends connected by detachable hook and eye means to the outer end portion of the arms 2'7 and 28, as shown more clearly in FIG- URES 3 and 4. With the holder in place, the spring extends around the outer portion of the tubular extension 15 and is sufficiently expanded to securely interlock the holder and extension. This arrangement is shown particularly in FIGURES l and 6. For connecting the holder and tubular extension, one end of the spring 30 can be temporarily disconnected and then expanded around the tube as it is reconnected, or the spring can be left connected to both arms and the holder slipped on over the tubular extension with the required expansion of the spring to permit the insertion to be made. It will be understood that other clamping and strap means can be used.

In accordance with the present invention, the holder 26 will contain electrical components of the voice amplification system. Preferably, the holder 26 includes the amplification speaker in one end portion thereof and the batteries for operating the speaker system in the other end portion thereof. In the illustration given, the outer portions of arms 27 and 28 respectively provide mounting receptacles for batteries and for a speaker. As shown in FIGURE 4, a plurality of batteries 31 are supported within arm 27, while a speaker 32 is mounted within arm 28. Preferably, the arm containing the batteries is provided at its outer end with a removable cover, such as the cover 33 on the end of arm 27 and which is removably held in place by means of a nut 34. As can be seen in FIGURE 4, by removing the cover 33, the batteries 51 can be readily replaced. The end of arm 27 is also provided with a cover and which in the illustration given consists of a ring 35 and a grille 36. If desired, the ring 35 and the grille 36 can be made removable, although ordinarily it will not be necessary for the user to obtain access to the speaker 32 during normal operation. Arm 28 also provides a speaker resonance chamber 37, as shown in FIGURE 4. The other electrical components of the system, some of which are also incorporated within the holder 26, will be subsequently described.

It is now desired to describe more particularly one preferred configuration of holder 26. As shown particularly in FIGURES 3-6, the forward wall 29a of the holder base portion 29 is shaped to receive and conform to the underside of the extension 15. In the illustration given, wall 29a and the underside of extension 15 are both of semi-circular shape. It will be understood that wall 29a will usually be of a curved or semi-circular Shape when employed with a tubular extension having a circular cross section. The shape of wall 29a can of course be varied to conform to other shapes of tubular extensions.

In the illustration given, the housing base portion 29 is provided with an upper surface, such as surface 2%, which has a concave or dished configuration. This permits the base of the holder to extend under the chin portion of the face piece, for example in the manner illustrated in FIGURES 1 and 5. As shown more clearly in FIGURE 5, the chin-conforming portion of the gas mask 12 (shown in dotted lines) is received within the reccssed upper surface portion of the holder, and lies in close proximity to the lower portion of the wall 2%. This arrangement assists in stabilizing the mounting of the holder, while permitting the holder to follow movements of the head of the wearer. The wearer can turn his head from side to side, or raise or lower his head without disturbing the mounting of the holder. With extension 15 connecting along the vertical center line of the mask, and the holder arms 27 and 28 extending outwardly on each side thereof, the weight of the holder is evenly balanced.

It will be appreciated by those skilled in the art that the speaker and electrical components contained within holder 26 will be connected to a microphone within face piece 10 so that the voice of the wearer of the mask can be transmitted with appropriate amplification to the speaker. The microphone mounting is shown particularly in FIGURE 2, where the microphone itself is desi gnated by the number as. Preferably, the microphone is removably mounted. In the illustration given, the microphone is provided as a one-piece assembly, with an arm 39 and a laterally-extending tube 40 which provides a threaded portion 41 for connection with a sleeve 42. As shown in FIGURE 2, the threaded portion 41 extends through an aperture in face piece 11, and is locked thereto by a guard sleeve 42. It will be understood that a gas-tight seal should be maintained, and for this purpose there can be provided an external sealing washer 43a, and an internal sealing ring 43b. As shown ring 43b is integral with face piece 11, but if desired a separate 0 ring can be used. The microphone assembly also includes a bayonet connector 44 within sleeve 42 for cooperating with a plug jack 45 that connects to a signal-transmitting line 46, as shown more clearly in FIGURE 1. It will be understood that line 46 connects the electrical components within holder 26.

With the construction just described, microphone 38 and the assoicated components, together with holder 26, can be readily removed from the gas mask. This is important, since gas masks frequently must be subjected to cleaning, sterilization, or decontamination, and these processes would be injurious for the voice amplification system components.

Since the wearer of the mask will usually not wish to have the speaker in operation at all times. the speaker system may be provided with an on and off switch, which should be conveniently located for use by the wearer of the mask. With the construction of this invention, the on and off switch may be mounted on the holder 26, for example, on one of the arms thereof. In the illustration given, an on-off switch 47 is mounted within the resonance chamber 37 in the arm 28, and is operated by means of a knob 48 on the outside of the arm. Operating knob 48 can also provide a volume control for the speaker, as is well-known in the voice amplification art.

Where desired, suitable connections and wiring extensions can be provided for other speakers in parallel with speaker 32. The other speakers may be in a master unit, or in similar holders of other gas masks. For example, arm 28 can be provided with a plug-in connector 49, as shown more clearly in FIGURES 4 and 6. A signal-transmitting line 50, with a suitable plug 51, can be attached to connector 49. As shown in FIGURE 1, cord 50 can extend to a plug 52 on the belt of the wearer, which in turn connects to a plug 53 with a signal-transmitting cord 54 that extends to a master unit 55.

The master unit would be used, for example, by a foreman of a tank cleaning crew. The foreman would be outside of the tank and thus would not be wearing a gas mask, while one or more workers within the tank would be equipped with gas masks of the type previously described having the voice amplification system. The system would be wired so that the voice of each wearer of a gas mask would be transmitted to the speaker of the master unit, and to the speakers of all other masks connected therewith. The master unit 55 would also contain a microphone immediately behind the grill 56 at one end thereof, the microphone being immediately in front of the speaker. By turning a control switch 57, the operator of the master unit could cut out the speaker and cut in the microphone. The microphone would be wired so that when the operator of the master unit spoke into it, the voice would be transmitted to the speakers of each of the gas masks, and amplified thereover. Alternatively, two or more gas mask voice amplification systems can be interconnected without the use of a master unit. Each gas mask unit would power the speakers of all the other gas masks.

As indicated in FIGURE 4, other electrical components of the voice amplification system can be included within holder 26. For example, transistor amplifier components and associated wiring, as indicated generally by the number 58, can be positioned within the central portion of the holder. To prevent disloding and damage of these components, they can be embedded within castdn-place packing material, such as a rigid polyurethane foam. The foam-type packing can also be used around the mounting for the batteries 31. In FIGURE 4, the foam material 59 is shown around the battery case 60 within arm 27.

An illustrative circuit diagram for the system is shown in FIGURE 7. The circuit is relatively conventional, and no claim to its novelty is made apart from the combination of the present invention. The upper portion of the diagram (above the broken line Y) is the circuit for the master unit, while'the portion below line Y is the circuit for the mask unit. It will be understood that both circuits include the elements enclosed within the box Z of the mask unit circuit, which is indicated in block form in the master unit circuit and designated by the same letter. The operation of the circuit may be briefiy described as follows:

Sounds picked up by the microphone 38 are transmitted to the amplifier through input jack I to volume control G, then through transistor input stage A to the driver stage consisting of transistor B and driver transformer B, then to the output stage consisting of pushpull transistors C and D and output transformer F. The center tap on the secondary winding of transformer E supplies bias voltage to transistors C and D. The secondary winding of F is connected to speaker H and remote jack K. Power is supplied by a battery L and controlled by an on-off switch M.

The master unit includes microphone N and is electrically identical to the mask unit except for the addition of a transmit-receive switch P. In operation, the master unit is wired as a receiver monitoring the sound coming from one or more mask units by wired connections between the jack K on all units. When the master wishes to talk to the mask units, he pushes the switch P to the transmit position. This reconnects'the unit as a transmitter and sends the signal from the master microphone N through the master amplifier and back through the wires to the jacks K and the speakers H of the mask units.

When more than one mask units are wired together between jacks K, all sounds picked up from any mask unit microphone N will be heard through all mask unit speakers H.

While in the foregoing specification this invention has been described with respect to a specific embodiment thereof, and a number of preferred features have been 6 discussedwith respect to this embodiment, it will be apparent to those skilled in the art that the invention is susceptible to other embodiments and that certain of the features described herein can be omitted or varied without departing from the broader aspects of the present invention.

I claim:

1. In combination with a gas mask face piece equipped with a tubular extension providing air passage means therein and projecting outwardly from the lower portion of said face piece, a holder mounted on said extension, electrical components of avoice amplifier system supported within said holder, said holder being characterized by a tubular housing having a generally U-shaped configuration, the base portion of said U receiving the underside of said extension and the arms of said U extending outwardly around said tubular extension, and means being provided for securing said arms around said tubular extension.

2. The combination of claim 1 wherein the outer end portions of said housing arm portions interiorly provide respectively mounting receptacles for a voice amplifying speaker and batteries for powering said speaker, and wherein a cover is removably mounted on the outer end of said arm providing said battery mounting.

3. In combination with a gas mask face piece having face-conforming peripheral portions including a chin portion, said face piece being equipped with a tubular extension providing air passage means therein and projecting outwardly from the lower portion of said face piece, over said chin portion, a holder mounted on said extension, electrical components of a voice amplifier system supported within said holder, said holder being characterized by a tubular housing having a generally U- shaped configuration, the base portion of said U receiving the underside of said extension and the arms of said U extending outwardly around said extension, said housing base portion having an upper surface extending to a position beneath the said chin portion of said mask.

4. The combination of claim 3 wherein the outer end portions of said housing arm portions interiorly provide respectively mounting receptaclesfor a voice amplifying speaker and batteries for powering said speaker, and wherein a cover is removably mounted on the outer end of said arm providing said battery mounting.

5. In combination with a gas mask face piece formed of a flexible material and equipped with a relatively rigid tubular extension providing air passage means therein and projecting outwardly and downwardly from the lower portion of said face piece, a holder detachably mounted on said extension, electrical components of a voice amplifier system supported within said holder, said holder being characterized by a tubular housing having a generally U- shaped configuration, the base portion of said U receiving and conforming to the underside of said extension, and the arms of said U extending outwardly around said tubular extension, said housing base portion having an upper surface extending to a position beneath the lower end of said face piece, said upper surface having a concave configuration, and means being provided for removably securing said holder arms around said tubular extension.

6. The combinatoin of claim 5 wherein said face piece is also provided with a removably mounted microphone, and signal conductor. means is detachably connected between said microphone and said holder, whereby said microphone, said signal conductor means, and said holder can be readily removed from said face piece.

7. In combination with a gas mask face piece having face-conforming peripheral portions including a chin portion, said face piece being equipped with a tubular extension providing air passage means therein and projecting outwardly from the lower portion of said face piece over said chin portion, said tubular extension being relatively rigid compared to said face piece, a holder detachably mounted on said extension, electrical components of a voice amplifier system supported within said holder, said holder being characterized by a tubular housing having a generally U-shaped configuration, the base portion of said U receiving and conforming to the underside of said extension and the arms of said U extending outwardly around said extension, said housing base portion having an upper surface extending to a position beneath the said chin portion of said mask, said upper surface having a dished configuration to permit said surface to be disposed in close proximity to said chin-conforming portion of said mask.

8. The combination of claim 7 wherein said holder is detachably mounted on said extension by releasable strap means extending between the outer end portions of the arms of said U over the upper side of said extension.

9. The combination of claim 8 wherein the outer end portions of said housing arm portions interiorly provide respectively mounting receptacles for a voice amplifying speaker and batteries for powering said speaker, and wherein a cover is removably mounted on the outer end of said arm providing said battery mounting.

10. In combination with a gas mask face piece formed of a flexible material and equipped with a tubular extension providing air passage means therein and projecting outwardly and downwardly from the lower portion of said face piece, said air passage means including concentric air supply and discharge passages and said tubular extension being relatively rigid compared to said face piece, a holder detachably mounted on said extension, electrical components of a voice amplifier system supported within said holder, said holder being characterized by a tubular housing having a generally U-shaped configuration, the forward wall of the base portion of said U receiving and conforming to the underside of said extension, and the arms of said U extending outwardly around said tubular extension, said housing base portion having an upper surface extending to a position beneath the lower end of said face piece.

References Cited by the Examiner UNITED STATES PATENTS 2,684,066 7/54 Glidden 128--141 2,937,244 5/60 Weinger 179--188 2,950,360 8/60 Duncan 179--146 2,974,665 3/61 Motsinger 128-141 RICHARD A. GAUDET, Primary Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2684066 *Nov 13, 1951Jul 20, 1954Acme Prot Equipment CompanyPressure regulator structure for pressure-type gas masks
US2937244 *Oct 4, 1957May 17, 1960Jetronic Ind IncElectrical-acoustic transducer
US2950360 *Nov 27, 1956Aug 23, 1960Baldwin Piano CoMicrophone support structure
US2974665 *Feb 12, 1954Mar 14, 1961Motsinger Armard VGas mask speech transmission
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3471642 *Aug 25, 1966Oct 7, 1969American Optical CorpCommunications headset with transmitter and receiver located in a noise-shielding cup covering mouth
US4116237 *Feb 7, 1977Sep 26, 1978Norman BirchEmergency breathing apparatus
US4374301 *Sep 18, 1980Feb 15, 1983Gentex CorporationLocal external communication device for enclosed helmet and mask assembly
US4400591 *Jul 17, 1981Aug 23, 1983Jennings Daniel ESimulated space helmet
US4475248 *Jun 1, 1982Oct 9, 1984Canadian Patents & Development LimitedExplosive ordinance disposal helmet
US4508936 *May 6, 1982Apr 2, 1985Gentex CorporationLocal external communication system
US4595003 *Oct 21, 1983Jun 17, 1986The United States Of America As Represented By The Secretary Of The ArmyProtective mask for airborne toxic substances
US4736740 *Sep 9, 1985Apr 12, 1988Robin ParkerGas mask with voice communication device
US4756308 *Oct 23, 1985Jul 12, 1988Akg Akustische U.Kino-Gerate Gesellschaft M.B.H.Protective breathing mask having a speaking diaphragm for close communication and an electroacoustic transducer system for indirect speech transmission from inside the mask
US4901356 *Dec 18, 1987Feb 13, 1990Actron Manufacturing CompanyVoice transmission system
US5138666 *Sep 9, 1991Aug 11, 1992Actron Manufacturing CompanyVoice transmission system
US5224473 *Mar 4, 1991Jul 6, 1993Bloomfield John WRetrofitting gas mask voice amplifier unit with easily actuated switch means
US5224474 *Jun 10, 1991Jul 6, 1993Bloomfield John WRetrofitting gas mask voice amplifier unit with easily actuated switch means
US5371804 *Nov 15, 1991Dec 6, 1994Actron Manufacturing CompanyVoice transmission system
US5428688 *Mar 29, 1993Jun 27, 1995Audiopack Sounds SystemsVoice transmission system with remote microphone
US5463693 *Nov 10, 1993Oct 31, 1995Audiopack Sound Systems Inc.Voice amplification adapter assembly for face mask
US5503141 *Jan 13, 1995Apr 2, 1996Kettl; Lonnie J.Microphone mounting structure for a sound amplifying respirator
US5603117 *Sep 13, 1995Feb 18, 1997The United States Of America As Represented By The Secretary Of The ArmyProtective helmet assembly
US5860417 *Feb 29, 1996Jan 19, 1999Kettl; Lonnie JoeMicrophone mounting structure for a sound amplifying respirator and/or bubble suit
US6412485 *Dec 11, 1998Jul 2, 2002Carl J. SaievaSurface breathing vent for breathing apparatus
US6430298 *Dec 1, 1997Aug 6, 2002Lonnie Joe KettlMicrophone mounting structure for a sound amplifying respirator and/or bubble suit
US6978034 *Jul 30, 2002Dec 20, 2005Lazzeroni John JHelmet headset mounting assembly and method
US7234462 *Feb 4, 2002Jun 26, 20073M Innovative Properties CompanySpeech transmission adaptor for use with a respirator mask
US7302072 *May 14, 2004Nov 27, 2007Ultra Electronics Audiopack Inc.Electronic device mount for mask
US7493899 *Jul 24, 2003Feb 24, 2009Selex Comunications LimitedMicrophone adaptor for a respirator
US7616774Oct 21, 2005Nov 10, 2009Lazzeroni John JClampless headset mounting assembly
US9344781Sep 23, 2013May 17, 2016Dolores Speech Products, LlcCommunication and speech enhancement system
US20020176595 *Jul 30, 2002Nov 28, 2002Lazzeroni John JClampless headset mounting assembly
US20040194782 *Jul 24, 2003Oct 7, 2004John DaviesMicrophone adaptor for a respirator
US20050008183 *May 14, 2004Jan 13, 2005Greg SkillicornElectronic device mount for mask
US20050197172 *Apr 27, 2005Sep 8, 2005John DaviesMicrophone adaptor for a respirator
US20060034477 *Oct 21, 2005Feb 16, 2006Lazzeroni John JClampless headset mounting assembly
DE3127677A1 *Jul 14, 1981Apr 29, 1982Gentex CorpSprechgeraet fuer maskentraeger
EP0304641A1 *Jul 25, 1988Mar 1, 1989SGE SOCIETA' GENERALE ELASTOMERI S.p.A.Protective mask
Classifications
U.S. Classification128/201.19, 2/6.6, D24/110.2, 2/6.7, 381/75, 381/376
International ClassificationA62B18/00, A62B18/08
Cooperative ClassificationA62B18/08
European ClassificationA62B18/08