Loudspeaker with short circuit rings at the voice coil
US5815587A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 17, 1997 |
| Grant date | Sep 29, 1998 |
| Priority date | — |
| Expiry date | Apr 17, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R9/04
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention is a loudspeaker. The loudspeaker includes a driver diaphragm having a voice coil and an associated magnet system including an annular air gap within which the voice coil locates, the voice coil being longer than the axial extension of the annular air gap, the magnet system including a central pole piece, the voice coil and central pole piece having a frontal end towards said driver diaphragm and a rearward end away from said driver diaphragm, the magnet system further comprising a cylinder arrangement, of a material and of a wall thickness sufficient to provide a conductivity suitable to act as a short circuit ring carrying compensating induction currents, the cylinder arrangement comprising a root part at a root area of the pole piece and an inner pole ring part rearward of the annular gap, the root part being located outside the rearward end of the voice coil when the voice card assumes a position of rest, and further comprising an outer pole ring part located forward of the annular gap, the inner pole ring part and the outer pole ring part both being shorter than half a length of the voice coil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.