Patent · US Expired

Stiffness variation device

US4243838A · kind A · utility

5Cited by
3References
17Claims
0Family size

Inventor

Key dates

Filing dateAug 23, 1978
Grant dateJan 6, 1981
Priority date
Expiry dateAug 23, 1998

Classification

  • Technology area (CPC H)Electricity
  • CPC primaryH04R9/025
  • WIPO fieldAudio-visual technology
  • WIPO sectorElectrical engineering

Abstract

This invention relates to an electromechanical apparatus for varying stiffness and is especially useful in electrodynamic systems, such as electrodynamic loudspeakers, to improve their low frequency response.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.