Earmuff
US5970160A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1997 |
| Grant date | Oct 19, 1999 |
| Priority date | — |
| Expiry date | Jul 10, 2017 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61F11/14
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Earmuff and method for changing the noise attenuation characteristic of an earmuff. The change is obtained by providing foam-filled sealing ring of the earmuff in the annular covering thereof with a large number of ventilation apertures which are uniformly distributed along the sealing ring, thereby affecting the air spring action of the sealing ring. The ventilation apertures communicate with the environment without communicating with interior of the earmuff. By reducing the air spring action to a considerable extent, the low frequency attenuation is improved. The communication with the environment provides "acoustic ducts", particular by using special ventilation ducts which can be dimensioned to give a selective noise transmission, dependent on the duct resonance, into the sealing ring, thereby selectively affecting the noise attenuation characteristic.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.