Patent EA-001014-B1 (EA)
Title: Electro-magnetic exciter
Inventor: AZIMA HENRY
IPC: H04R11/02
Filed: 1998-01-30
Abstract: 1. An electro-dynamic inertial vibration exciter (1) for exciting a member (2) having capability to sustain and propagate input vibrational energy comprising a motor coil assembly (3,4) having a coil (3) rigidly fixed to a tubular coil former member (4), a magnet assembly (5, 6, 7) disposed concentrically with respect to the motor coil assembly, means (11) suspending the magnet assembly for axial movement relative to the motor coil assembly, and a carrier (9) supporting the motor coil assembly (3,4) and adapted for connection to the member (2) to be excited, characterised by a coupling member (12) adapted to interfit with the magnet assembly (5, 6, 7), and in that the suspension means (11, 23, 24) is connected between the carrier (9) and the coupling member (12). 2. An inertial vibration exciter according to claim 1, characterised in that the carrier (9) is directly connected to the coil former member (4). 3. An inertial vibration exciter according to claim 1 or 2, characterised by means (13) on the coupling member and on the magnet assembly for fixing the coupling member and magnet assembly together. 4. An inertial vibration exciter according to claim 3, wherein the fixing means comprises latch means (13). 5. An inertial vibration exciter according to any preceding claim, wherein the carrier (9) and the suspension means (11, 23, 24) are integral. 6. An inertial vibration exciter according to any preceding claim, characterised in that the coupling member (12) and the suspension means (11, 23, 24) are integral. 7. An inertial vibration exciter according to any preceding claim, characterised in that the suspension (11, 23, 24) is resilient. 8. An inertial vibration exciter according to claim 7, characterised in that the suspension (11,23) is formed as a diaphragm. 9. An inertial vibration exciter according to any one of claims 1 to 7, characterised in that the suspension (24) comprises a set of resilient arms (28). 10. An inertial vibration exciter according to claim 9, when dependent on claim 4, characterised in that the coupling member (12) and the carrier (9) are annular and in that the arms (28) are connected between the coupling member (12) and the carrier (9) to extend circumferentially. 11. An inertial vibration exciter according to claim 10, characterised by a dust seal (10) closing the annular carrier (9). 12. An inertial vibration exciter according to any preceding claim, characterised in that the carrier (9) has a face adapted for contact with the member (2). 13. An inertial vibration exciter according to any preceding claim, characterised in that an axial end (17) of the coil former member (4) is located and mounted in a recess (18) in the carrier (9). 14. An inertial vibration exciter according to any preceding claim, characterised in that the coil (3) is mounted on the outer face of the coil former member (4). 15. An inertial vibration exciter according to any preceding claim, characterised in that the magnet assembly  (5,6,7) comprises opposed generally disc-like pole pieces (6,7) sandwiching a magnet (5), the periphery of one (7) of which pole pieces is disposed within and adjacent to the motor coil assembly (3,4), and the periphery of the other (6) of which pole pieces is formed with a downturned flange (8) arranged to lie adjacent to and to surround the motor coil assembly (3,4) to form a coil receiving gap (20). 16. An inertial vibration exciter according to claim 15, characterised in that the flange (8) is adapted to interfit with the coupling member (12). 17. An inertial vibration exciter according to claim 10; characterised by a lip (22) on the flange (8), which lip is shaped to interfit with the coupling member (12), and by fixing means (13) on the coupling member and is adapted to engage the lip (22). 18. An inertial vibration exciter according to any preceding claim, characterised in that the suspension (24) comprises an axially spaced pair of suspension components (28) which are formed integrally one with the other. 19. An inertial vibration exciter according to claim 18, characterised in that the axially spaced pair of suspension components (28) are moulded integrally with the coil carrier (9) and with a coupling member (12) for engaging and supporting the magnet assembly. 20. An inertial vibration exciter according to claim 19, characterised in that the suspension components (28) comprise respective sets of resilient arms (28) each of which is associated with a respective coupling member (12). 21. A loudspeaker comprising an inertial vibration exciter as claimed in any preceding claim.