SHAKER-TYPE TRANSDUCER WITH CENTERING DEVICE

• US 20120170795A1
• Filed: 09/02/2010
• Published: 07/05/2012
• Est. Priority Date: 09/09/2009
• Status: Active Grant

• Current Assignee: ASK Industries Societa' Per Azioni
• Original Assignee: ASK Industries Societa' Per Azioni
• Inventors: Sancisi, Carlo, Falcioni, Andrea
• Granted Patent: US 8,792,671 B2
• Time in Patent Office: Days
• US Class Current: 381/413
• CPC Class Codes: H04R 9/043 Inner suspension or damper, e.g. spider outer suspension or surround H04R7/16
• CPC Class Codes: H04R 9/066 using the principle of inertia

Abstract

A shaker transducer is disclosed, which comprises a magnetic unit (1) composed of a magnet (3) disposed between a first polar plate (2) and a second polar plate (4) in such a way to generate a toroidal air gap (5). A sound coil (6) is disposed in the air gap (5) to move axially and a centering element (100) is fixed to the coil to maintain it centered with respect to the magnetic unit (1). A rigid element (10) comprising a shank (12) fixed to said cylindrical support (61) of the sound coil and adapted to be anchored to a surface to transfer the sound vibrations generated by the magnetic unit (1). The centering element (100) comprises a central cylindrical shank (101) fixed to the coil, a peripheral shank (102) fixed to the second polar plate (4) and a plurality of elastic spokes (103, 103′) disposed between said central shank (101) and said peripheral shank (102).

Claims

1. Shaker-type transducer comprising:

a magnetic unit composed of a magnet disposed between a first polar plate and a second polar plate to a toroidal shaped air gap,

a sound coil comprising an empty cylindrical support with winding, said sound coil being arranged in the air gap and said cylindrical support having an upper part that protrudes externally from said second polar plate,

a centering element positioned between said magnetic unit and said sound coil and configured to maintain the coil centered with respect to the magnetic unit during the relative axial movement of the coil with respect to the magnetic unit and vice versa,

a rigid element comprising a shank connected to said cylindrical support of the sound coil and adapted to be anchored to a surface to transfer the sound vibrations generated by the magnetic unit,

said centering element comprises

a central cylindrical shank fixed to said protruding portion of the cylindrical support of the coil or to said magnetic unit,

a peripheral cylindrical shank fixed to said magnetic unit or said cylindrical support of the sound coil, said peripheral cylindrical shank being higher than the central shank, and

a plurality of elastic spokes disposed between said central shank and said peripheral shank, wherein said spokes are shaped as a flat plate with respect to a plane orthogonal to the axis of the central shank coinciding with the axis of the coil, said spokes having a lower thickness than the height of said central shank and being equally spaced,

said centering element comprising a first set of spokes that lie on a first plane orthogonal to the axis of the central shank and at least a second set of spokes that lie on at least a second plane orthogonal to the axis of the central shank, at a certain distance from said first plane.

2. Shaker-type transducer as claimed in claim 1, wherein the spokes of the first set are angularly equidistant and the spokes of the second set are angularly equidistant and staggered with respect to the spokes of the first set.

3. Shaker-type transducer as claimed in claim 1, wherein the spokes are made of plastic material coated with damping material.

4. Shaker-type transducer as claimed in claim 1, wherein the cylindrical support of the sound coil is filled with damping material.

5. Shaker-type transducer as claimed in claim 1, wherein the centering element is obtained in one piece by molding plastic materials.

6. Shaker-type transducer as claimed in claim 1, wherein the centering element is made by assembling two parts.

7. Shaker-type transducer as claimed in claim 1, wherein said centering element comprises fit-in or bayonet coupling means in order to allow for self-centering of the sound coil in the air gap of the magnetic unit.

8. Shaker-type transducer as claimed in claim 1, wherein said central cylindrical shank of the centering element is fixed to said protruding portion of the cylindrical support of the coil;

and said peripheral cylindrical shank is fixed to said second polar plate of the magnetic unit.

9. Shaker-type transducer as claimed in claim 8, wherein said upper polar plate comprises a core disposed inside a toroidal magnet and a toroidal lower polar plate and said transducer also comprises two magnets with opposite polarity disposed inside said cylinder of the sound coil, a first magnet fixed to the core of the upper polar plate and a second magnet fixed to the cylinder of the sound coil to obtain magnetic damping and contribute to general stretchiness mainly generated by the system of elastic spokes.

10. Shaker-type transducer as claimed in claim 1, wherein

said upper polar plate of the magnetic unit is shaped as a cup;

said central shank of the centering element is fixed to said cup of the magnetic unit, and

said rigid element for transfer of sound vibrations comprises a shank fixed to said cylindrical support of the sound coil and is shaped as a lid that is fixed to said cylindrical support of the sound coil.