Patent ID: 8792671

Claim:
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 a cylindrical support with winding, said sound coil being arranged in the air gap and said cylindrical support having a protruding portion 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, the spokes of the first set being angularly equidistant and the spokes of the second set being angularly equidistant and staggered with respect to the spokes of the first set, said centering element thereby configured so as to be capable of being injection-molded from plastic materials using only one mold.