Blast Attenuating Earplug

• US 20130152949A1
• Filed: 12/13/2012
• Published: 06/20/2013
• Est. Priority Date: 12/20/2011
• Status: Active Grant

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Simon, Daniel H.
• Granted Patent: US 9,138,352 B2
• Time in Patent Office: Days
• US Class Current: 128/868
• CPC Class Codes: A61F 11/08 internal, e.g. earplugs
• CPC Class Codes: A61F 11/085 including an inner channel

Abstract

An earplug includes a body, insertable into an ear canal, where the body defines a channel having at least two ends. The channel can house a movable structure configured to allow passage of sound around the movable structure in a rest position, and to block at least a portion of the channel in a deflected position. The movable structure moves from the rest position to the deflected position based on receiving, at one of the at least two ends of the channel, a pressure wave having at least a threshold amplitude pressure to block at least a portion of the pressure wave from reaching the other end of the channel.

Claims

1. An earplug comprising:

a body insertable into an ear canal, the body defining a channel having at least two ends; and

a movable structure disposed within the channel and configured to;

allow passage of sound around the movable structure in a rest position within the channel,

block at least a portion of the channel in a deflected position within the channel, and

move from the rest position to the deflected position based on receiving, at one of the at least two ends of the channel, a pressure wave having at least a threshold amplitude pressure.

2. The earplug of claim 1, wherein the movable structure is further configured to move from the deflected position to the rest position following a reduction in amplitude pressure of the pressure wave to below the threshold amplitude pressure.

3. The earplug of claim 1, wherein the movable structure is further configured to move toward another deflected position toward an opposite end of the channel of the deflected position based on a rarefaction portion of the pressure wave.

4. The earplug of claim 1, wherein the channel defines a cavity and the movable structure is disposed within the cavity.

5. The earplug of claim 4, wherein the movable structure is disposed at the rest position within the cavity using an adhesive.

6. The earplug of claim 4, wherein the movable structure is biased to the rest position within the cavity using a magnetic or electrostatic force.

7. The earplug of claim 4, further comprising a retaining mechanism for attaching the movable structure to a portion of the channel within the cavity to support the movable structure position at the rest position.

8. The earplug of claim 7, wherein the retaining mechanism is configured to flex based on the movable structure being subjected to the pressure wave to move the movable structure from the rest position to the deflected position when pressure wave is at least at the threshold amplitude pressure, or from the deflected position to the rest position following a reduction of amplitude pressure of the pressure wave to below the threshold amplitude pressure.

9. The earplug of claim 7, wherein the retaining mechanism is configured to break based on the movable structure being subjected to the pressure wave having at least the threshold amplitude pressure to move the movable structure to the deflected position.

10. The earplug of claim 7, wherein the retaining mechanism comprises a cantilevered beam extending radially inward from a sidewall of the channel.

11. The earplug of claim 1, wherein a size of the movable structure is larger than a width of the channel.

12. The earplug of claim 1, wherein the movable structure is composed of expanded polystyrene, an aerogel formulation, a multilayer material, or a composite material.

13. The earplug of claim 1, wherein the movable structure is substantially hollow or porous.

14. The earplug of claim 1, wherein the body comprises an exterior portion and an interior portion, wherein the interior portion defines the channel.

15. The earplug of claim 14, wherein the exterior portion is composed of a flexible material, and the interior portion is composed of a rigid material.

16. The earplug of claim 15, wherein the flexible material comprises a silicon rubber or a memory foam.

17. The earplug of claim 1, wherein

the at least two ends are disposed at opposite longitudinal ends of the body,

the channel comprises one or more passive acoustic fitters configured to deform upon receiving pressure waves having at least another threshold amplitude pressure, and

the one or more passive acoustic filters include one or more membranes or orifice plates.

18. The earplug of claim 1, wherein the channel comprises an inlet portion and an outlet portion, and wherein the movable structure is disposed between the inlet portion and the outlet portion.

19. The earplug of claim 18, wherein the movable structure contacts the outlet portion when in the deflected position.

20. The earplug of claim 19, wherein the movable structure contacts the outlet portion such to block the pressure wave having at least at the threshold amplitude pressure from reaching the outlet portion.