Blast Attenuating Earplug
The use of IEDs in Iraq and Afghanistan has made hearing damage the #1 disability of returning veterans. Similar situations occur in industry and in everyday life. Ear injuries are often untreatable after they occur and victims suffer a lifetime of symptoms. Current choices for hearing protection fall short of ear protection needs.
Present mechanical earplug technology uses a variety of constructions, which may provide benefits in different high noise environments. Some constructions use a sound deadening material, such as foam, to block or lessen sounds entering the ear canal. Other constructions include acoustic filters, such as cavities, side branches, other apertures for redirecting sound waves, or vibrating diaphragms for absorbing sound waves. Some earplugs attenuate sounds based on acoustic frequency. This allows discerning sounds of useful frequencies, such as those used in speech, while blocking sounds of potentially harmful ones. This however, may prevent an individual using the earplug from hearing some useful sounds that may be out of the designated frequency range. Electronic earplugs exist as well for actively attenuating or amplifying sound. Such earplugs use microphones, electronic circuitry, speakers, and a power source, which add to the cost of the earplug and may require some maintenance to ensure operation via power source and/or circuitry. A more simple and elegant solution is needed.
Researchers at the Johns Hopkins Applied Physics Laboratory (JHU/APL) have developed the Blast Attenuating Earplug (BAE), which presents a simple solution to this huge problem. These devices can be manufactured inexpensively for wide distribution. The BAE wouldn't impact the userís ability to do their job; therefore, they would be more inclined to use them.
The BAE attenuates sound based, at least in part, on an amplitude pressure. For example, a BAE can be constructed to allow passage of sounds less than a threshold amplitude pressure, while blocking pressure waves that achieve or exceed it. The BAE has a body that defines a channel having two ends that remain substantially open to allow transmission of soft sounds received with little or no attenuation. The BAE will react to large amplitude pressure by closing or otherwise blocking at least a portion of the channel to mitigate passage of sound related to the large amplitude pressure.
The BAE fits within an ear canal, and can include a movable structure defined in the channel. The movable structure can be initially positioned within the channel to allow passage of sound. When a wave of a threshold amplitude pressure is received at the end of the channel, the movable structure can move to block at least a portion of the wave. This prevents the wave from reaching the other end. The movable structure is larger than part of the channel to allow the blocking. For example, when the wave of the threshold amplitude pressure is reduced below the threshold or otherwise no longer received, the movable structure can be repositioned within the channel to allow passage of sound.
We are seeking a commercial transition licensee, either a start-up or an existing company, focusing on non-US Government customers who can successfully commercialize this IP.
Patent Status: U.S. patent 9,138,352 issued.
Dr. G. R. Jacobovitz
Phone: (443) 778-9899