TECHNICAL FIELD

This disclosure relates to a system and method for converting passive ear muff protectors to an over-the-ear headset or headphones that may include active and passive noise reduction and audio communication technology.

BACKGROUND

Passive hearing protection may include two earcups or muffs joined by a headband and worn over ears of users to enhance or protect hearing. Active and passive attenuation may be provided to protect hearing, reduce loudness of ambient noise, and improve user hearing of desired sounds. Both active and passive attenuation vary as a function of frequency. Various strategies have been developed to provide desired attenuation across frequency ranges of interest. Passive attenuation may be improved by reducing noise leak paths into the ear. However, there are design compromises between user comfort and pressure of the earcups to reduce leak paths. As such, performance can vary from person to person based on how well the earcups fit the head of a user. Significant research and development resources have been expended to engineer and design ear muff shapes and select materials that provide desired performance with respect to passive attenuation, weight, and comfort.

SUMMARY

In various embodiments, a modular insert for an ear muff having an external shell includes a frame configured for positioning within the external shell and having a first support adapted to contact an interior of the external shell and a second circumferential support cooperating with a seal to contact an ear seal plate of the ear muff to define a back cavity between the interior of the shell and the frame and a front cavity between the frame and a user's head. The frame may include an aperture configured to receive a speaker supported by the frame between the front cavity and the back cavity, and supports to secure circuitry coupled to the speaker within the back cavity. The external shell may include or may be modified to include a resistive vent that vents the back cavity to atmosphere.

The modular insert may be used to convert ear muffs to a communication headset which may include a boom microphone. Alternatively, a wired microphone or wireless microphone may be coupled to circuitry on the modular insert. Active noise reduction (ANR) circuitry components may also be provided. For ANR applications, the frame may be configured to support a sense microphone coupled to the circuitry to provide (ANR) operation using the speaker. The resistive vent may include an integrated ambient microphone coupled to the circuitry to provide a feedforward signal for use by the ANR control system. The frame may also be configured to support one or more rechargeable batteries within the back cavity to power the circuitry. The circuitry may include a wired or wireless transceiver to send and receive audio and voice signals using various technologies and protocols, such as Wi-Fi, Bluetooth, Wi-Max, etc.

Embodiments according to the disclosure may provide one or more associated advantages. For example, inserts according to the disclosure leverage previous research and development of ear muffs that provide desirable passive attenuation for conversion to communication headsets or ANR headsets. The components and circuitry for wired or wireless communication or ANR headsets can be mounted to an insertable frame installed within the ear muffs that provides a sealed front cavity to maintain or improve desirable passive attenuation characteristics. Similarly, passive attenuation performance may be maintained by connection of any components that require an external wire or other connection, such as a boom microphone or ambient microphone, through the earmuff external shell into the back cavity. The modular characteristics of the insertable frame may reduce part counts and provide manufacturing flexibility for multiple models of communication and ANR headsets using existing muff/earcup designs and associated existing tooling. Frame shape and positioning may be selected to provide a desired volumetric or other ratio between the back cavity and the front cavity to improve speaker/driver power efficiency and resulting battery life associated with a relatively large back cavity volume. Circuitry installed on the modular frame insert may be tested to assure desired performance prior to assembly within the muffs.

The above advantages and other features and advantages may be recognized by those of ordinary skill in the art based on the following detailed description and accompanying drawings of one or more representative embodiments.

