EP 0083045 A3 19830928 - MAGNETIC SYSTEM WITH ANNULAR AIR-GAP, IN PARTICULAR FOR WOOFERS
Title (en)
MAGNETIC SYSTEM WITH ANNULAR AIR-GAP, IN PARTICULAR FOR WOOFERS
Publication
Application
Priority
- DE 3151530 A 19811224
- DE 8226166 U 19820917
Abstract (en)
[origin: US4628154A] An annular gap magnet system, in particular for a low frequency loudspeaker (Woofer), in which a coil is movable with a large stroke in the working air gap. A braking air gap provided in the region of the inner or lower pole plate produces a magnetic resistance in the pole plate so that a part of the magnetic flux flows over the braking air gap. This magnetic flux is opposed to the stray magnetic flux below the working air gap and excites a counter magnetic field which opposes further inward movement of the moving coil. In this way an impact of the moving coil against the inner or lower pole plate is prevented. In a low frequency loudspeaker the membrane carrying the moving coil may, therefore, be suspended extremely softly.
IPC 1-7
IPC 8 full level
H04R 9/02 (2006.01)
CPC (source: EP US)
H04R 9/025 (2013.01 - EP US); H04R 2209/022 (2013.01 - EP US)
Citation (search report)
- GB 858250 A 19610111 - DARWINS LTD
- DE 1614164 A1 19700625 - MAGNETFAB BONN GMBH
- GB 1321581 A 19730627 - ROLA CELESTION LTD
- DE 2211818 A1 19730913 - WHITE STANLEY F
- FR 2382822 A1 19780929 - SEAS FABRIKKER AS [NO]
- FR 2304238 A1 19761008 - LICENTIA GMBH [DE]
- DE 574429 C 19330418 - LOEWE OPTA GMBH, et al
- [A] PATENTS ABSTRACTS OF JAPAN, Band 6, Nr. 28, (E-95)[906], 19. Februar 1982 & JP - A - 56 146 400 (MATSUSHITA DENKI SANGYO K.K.) 13.11.1981
Designated contracting state (EPC)
DE FR GB IT
DOCDB simple family (publication)
EP 0083045 A2 19830706; EP 0083045 A3 19830928; EP 0083045 B1 19851121; DE 3267630 D1 19860102; US 4628154 A 19861209
DOCDB simple family (application)
EP 82111770 A 19821218; DE 3267630 T 19821218; US 45276982 A 19821223