Patent ID: 7683508
Filing Date: 2010-03-23
Classification: H01F,H02K

Abstract:
1. A vibration device, comprising: a coil for generating an electromagnetic field, the coil being affixed at a first end to a body; a moveable mass of magnetic material at least partly encircled by the coil; and a nonlinear spring device coupled at a first end thereof to the moveable mass and affixed at a second end thereof to the body; wherein the moveable mass is operable to move linearly relative to the body upon generation of the electromagnetic field by the coil and to transfer a vibratory force to the body as the mass moves; and wherein a resonant frequency of the vibration device increases as a stiffness of the nonlinear spring device increases and wherein the resonant frequency of the vibration device decreases as the stiffness of the nonlinear spring device decreases, and wherein the nonlinear spring device is a hardening spring device.