The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 18, 1977
Filed:
Mar. 16, 1976
James H Ott, Akron, OH (US);
Novar Electronics Corporation, Barberton, OH (US);
Abstract
A device for use in an enclosure associated with an audio speaker or other sound producing device and which permits relatively large volume changes within the enclosure as a result of relatively small pressure changes so that relatively small enclosures can be as effective as enclosures of larger volume. The device reduces the energy required from the speaker to change the volume of the interior of the enclosure. The device has a displaceable walled container having an expansible and contractible volume containing a composition of matter at gas phase/liquid phase equilibrium at its boiling point under atmospheric or other ambient pressure. The composition of matter preferably selected is one having the characteristic that relatively large volumes undergo a phase change for relatively small energies. The composition is heated to its boiling point. The heater is actuated by a volume responsive switch to maintain the container within a selected range of volume. Pressure perturbations caused by movement of the vibratorily driven membrane of the sound producing device cause alternate condensation and vaporization of the composition of matter to minimize backpressure.